Method for forming an omniphobic layer

Abstract

One aspect relates to a method for forming an omniphobic layer on an optical element (2) by immersion in a bath (11), comprising the steps of providing the optical element (S100), immersing the optical element in the bath (S110) and removing or exposing the optical element from the bath (S120), characterized in that the bath (11) has a pH value between 3.0 and 6.0, a film (12) is arranged or formed at the air-water interface of the bath (11), which film has at least the molecules (8) forming the omniphobic layer (6), and the omniphobic layer (6) has at least one organosilicon compound (8) or is or is formed thereby. Further aspects relate to an optical element (2) and a device (10).

Description

[0001] The present invention relates to a method for forming a monolayer of an omniphobic layer on an optical element, preferably a lens, particularly preferably a spectacle lens, as well as to an optical article comprising a monolayer of an omniphobic layer.

[0002] It is known to coat or coat optical elements, preferably lenses, more preferably ophthalmic lenses, and most preferably spectacle lenses, with a plurality of different layers. For example, coating with a hard coating protects the spectacle lens from scratches. Reflection reduction can be achieved by coating with an interference / anti-reflective coating. Coating with an omniphobic layer or a functional layer, sometimes also referred to as a topcoat or clean coat, ultimately serves to repel dirt and water droplets. Starting from the surface of the spectacle lens, a typical layer structure comprises at least a hard coating, an interference / anti-reflective coating, and a functional layer. The latter therefore represents the outermost coating layer. Each of the aforementioned coating layers can consist of a single layer or a layer system with several layers.

[0003] To repel dirt and water droplets, the functional layer typically has both oleophobic and hydrophobic properties, which is why it is referred to as an omniphobic layer in the present invention. A measure of the protective repellent effect is the respective contact angle that a corresponding liquid forms on the surface of the spectacle lens. In general, the larger the contact angle of the respective liquid on the surface of the spectacle lens, the more pronounced the oleophobic and hydrophobic properties become.

[0004] Functional layers used to date in the coating of ophthalmic lenses are usually based on per- and polyfluorinated alkyl substances (PFAS).

[0005] These are organic compounds in which the hydrogen atoms of the aliphatic carbon skeleton are fully replaced by fluorine atoms, i.e., perfluorinated, or partially replaced by fluorine atoms, i.e., polyfluorinated. All PFAS contain at least one trifluoromethyl group or one difluoromethylene group. Because PFAS and / or their degradation products are extremely persistent in the environment, they are also referred to as "forever chemicals." Furthermore, some PFAS are suspected of being carcinogenic. Given these disadvantages, there are international efforts to restrict their use.

[0006] For example, US 8 950 861 B2 describes a spectacle lens comprising a water-repellent, PFAS-containing film as the outermost layer, wherein this film was produced by a vapor deposition process by evaporating a coating material comprising a perfluorinated polyether silane compound, wherein this film is not further restricted with regard to its layer thickness.

[0007] Methods and devices for obtaining a Langmuir-Blodgett film are known from the prior art, which deal in detail with the formation of such a monomolecular film.

[0008] US 5 512 326 A describes a method and apparatus for forming a monomolecular film.

[0009] WO 2017 / 023 771 A1 also describes a method for forming a monomolecular film.

[0010] EP 3 189 899 B1 describes a device for obtaining nanostructured coatings on solid surfaces.

[0011] US 2019 / 0 217 580 A1 discloses an article with a water / oil repellent coating comprising a hydrolyzed condensate of a fluorinated compound with a hydrolyzable silyl group.

[0012] WO 2024 / 200 260 A1 discloses an article with a water / oil repellent coating comprising an organosilicon compound.

[0013] The publication “BIOLIN SCIENTIFIC: Langmuir and Langmuir-Blodgett Deposition Troughs Modules and accessories”, version 11 / 2020, https: / / www.biolinscientific.com / hubfs / Pdf / KSV%20NIMA / Brochures / KSV-NIMA-Land-LB-Modules-and-Accessories-for-web-2020-1.pdf, archived on January 27, 2021 at http: / / www.archive.org, discloses an apparatus for forming films using the Langmuir-Blodgett method.

[0014] An object of one aspect of the present invention is to provide an improved method for forming a monolayer of an omniphobic layer.

[0015] The problem is solved in particular by a method having the features of claim 1. The subclaims relate to advantageous developments.

[0016] One aspect of the present invention relates to a method for forming an omniphobic layer, in particular for forming a monolayer or a monomolecular layer of an omniphobic layer, on an optical element by immersion in a bath, comprising the steps: - Providing the optical element; - Immersing the optical element in the bath; - removing or submerging the optical element from the bath, wherein the bath has a pH value between 3.0 and 6.0, preferably between 3.5 and 5.5, particularly preferably between 4.0 and 5.0, a film is arranged or formed at the air-water interface of the bath, which film has at least the molecules forming the omniphobic layer and the omniphobic layer has at least one organosilicon compound or is or is formed thereby.

[0017] The proposed method relates to a method for forming an omniphobic layer, i.e. it relates to a manufacturing method, in particular a method for forming or producing an omniphobic layer on an optical element or for an optical element by immersion in a bath. In other words, the proposed method provides an optical element with an omniphobic layer or an omniphobic layer or omniphobic coating is formed or produced on an optical element. The method is preferably suitable for forming a monolayer or a monomolecular layer of such an omniphobic layer on the optical element, which in other words is understood to mean an omniphobic layer which is characterized by a layer thickness or physical layer thickness or wall thickness which corresponds approximately to one, in a further development preferably exactly one, molecular length of the molecule forming the omniphobic layer.The method is suitable for the precise formation of such an omniphobic layer, and in particular the method is suitable for the highly ordered application of such a layer.

[0018] An omniphobic layer is understood to be a layer or coating that exhibits omniphobic properties, preferably hydrophobic and / or oleophobic properties, and thus provides the optical element with advantageous repellency against water and dirt. The omniphobic layer is initially not further restricted.

[0019] Preferably, the omniphobic layer has a water-repellent effect, characterized by a contact angle with water of approximately 105°, and a grease- and dirt-repellent effect, characterized by a contact angle with hexadecane of approximately 40°, preferably approximately 45°. This makes the optical element highly suitable for everyday use, as the water- and dirt-repellent effect of the omniphobic layer tends to reduce the adhesion of dirt.

[0020] The omniphobic layer comprises at least one organosilicon compound or, in particular, the omniphobic layer is or will be formed by at least one organosilicon compound.

[0021] Organosilicon compounds (also: organosilicon compounds) is the collective term for compounds that either have direct silicon-carbon bonds (Si-C) or in which the carbon is linked to the silicon via oxygen, nitrogen, or sulfur atoms. Organosilicon compounds can be described by the general formula R n Six 4-n (with n from 1 to 4), where R represents various organic radicals, such as aliphatics, aromatics, and heterocycles. X represents various groups (see table). X Stoffgruppe H oder R Organosilan, z.B. Tetramethylsilan OH Organosilanole, z.B. Trimethylsilanol, CI Organochlorsilane Si-O Siloxane Si-N Polysilazane Si-C Carbosilane

[0022] The organosilicon compound may be a linear or open-chain compound, preferably comprising at least one carbon atom, at least one oxygen atom, at least one nitrogen atom, at least one halogen atom and / or at least one sulfur atom, each of which is linked to an associated silicon atom.

[0023] In a preferred embodiment, the preferably at least one organosilicon compound of the omniphobic layer has one or more functional groups, also referred to as so-called tail groups, which are responsible for the omniphobic properties, and has one or more coupling groups, also referred to as so-called anchor groups or head groups, which are responsible for the bonding, preferably for the bonding to a silicon oxide layer. In a further development of this, the preferably at least one organosilicon compound can also have further components, preferably at least one further molecular group, particularly preferably two or more molecular groups, as explained in the following paragraphs.

[0024] The functional group or functional chain or tail group of the preferably organosilicon compound has at least one alkyl group or one alkoxy group, represented by the structure -C n H 2n+1 - or -C n H 2n+1O-, where n is an integer that assumes values ​​of 4 or greater, preferably 8 or greater, particularly preferably 11 or greater. The properties of this alkyl group depend on its length or, more precisely, on the chain length of the alkyl group. This chain length is generally referred to as the C chain length based on the number of carbon atoms it contains. With regard to the length of the alkyl or alkoxy chain, substances with a chain length greater than or equal to C4 are preferred, particularly preferably with a chain length greater than or equal to 8, further preferably with a chain length greater than or equal to 11, since these enable the formation of SAMS (self-assembled monolayers) in addition to the hydrophobic properties that increase with increasing chain length. A longer alkyl or alkoxy chain in the tail group advantageously results in improved shielding of the coupling group, which is used to bind to the substrate.Good shielding advantageously leads to improved cleaning resistance, which means that such a connection survives a large number of cleaning strokes, whereby a cleaning stroke means the wiping movements typically present when cleaning a glass body of this type.

[0025] Preferably, at least one organosilicon compound has at least one hydrolyzable group as a coupling group or head group, which can react with water to form a silanol. Advantageously, the silanol can then bond to a silicon oxide layer of the optical element as part of a condensation reaction, as a result of which the organosilicon compound forms a covalent bond and the omniphobic layer is thus formed on the optical element. Preferably, the at least one hydrolyzable group is a chloro or methoxy group, a propoxy group, an amine, a silazane, an oxime or an acetoxy group; in particular, the hydrolyzable group is an ethoxy group. The number of coupling groups can vary from one to three, with further head groups or coupling groups being used instead of further coupling groups.In addition to the coupling groups, additional tail groups, i.e., omniphobic alkyl or alkoxy chains, can also be present, which can result in increased hydrophobicity or better shielding. In addition to van der Waals interactions that occur between the alkyl or alkoxy chains of the tail groups of neighboring molecules, the coupling groups can also lead to the formation of cross-linking through covalent bonding of the coupling groups of neighboring molecules, since not all coupling groups bind to the surface of the glass body or a silicon oxide layer located there. Both the van der Waals interaction and the cross-linking lead to the shielding of the substrate surface and the coupling groups, thereby improving the cleaning resistance of the omniphobic layer.

[0026] Preferably, at least one organosilicon compound of the omniphobic layer is hexadecyltriethoxysilane (CAS 16415-13-7) with the formula C22 H 48 O3Si, or in particular, the omniphobic layer is or will be formed by hexadecyltriethoxysilane. Also preferably, the organosilicon compound octadecyltriethoxysilane (CAS 7399-00-0) with the formula C 24 H 52O3Si or be or in particular the omniphobic layer is or is formed by octadecyltriethoxysilane. The chain length of the functional group or tail group, the alkyl chain, is C16 or C18 in the above cases. The above-mentioned organosilicon compounds are ethoxysilanes, whereby the organosilicon compound can alternatively or additionally contain chlorosilanes and / or methoxysilanes and / or propoxysilanes, more preferably hexadecyltrichlorosilane, hexadecyltrimethoxysilane, octadecyltrichlorosilane and / or octadecyltrimethoxysilane. With further preference, organosilicon compounds with an even longer alkyl chain can be used, in particular compounds with an alkyl chain length of C20 to C34, since these have greater strength because the longer the alkyl chain increases, the non-covalent interaction of the hydrocarbon radicals is favored, which to a greater extent promotes alignment orSelf-organization of the groups is required. Advantageously, a longer alkyl chain results in improved hydrophobic and oleophobic properties and improved cleaning resistance.

[0027] Organosilicon compounds which have a substantially linear molecular structure are preferably suitable for forming the omniphobic layer, which in particular means the presence of a substantially linear alkyl or alkoxy chain as a tail group.

[0028] The first step of the method comprises providing the optical element. Preferably, an object is used or provided that can be used as an optical element, for example, as a lens or ophthalmic lens or as a spectacle lens. However, the object is not limited to ophthalmic lenses and can be any transparent or optical object to which, in particular, a coating can be applied. Specific examples include glasses such as crown glass, mineral glass, window glass, flat glass, windshields or viewing windows, or elements of optical sensors, light sources or photographic lenses, or plastics such as polyacrylates or ceramics.

[0029] The optical element preferably consists of a transparent plastic, for example a transparent plastic substrate, which can be treated or untreated. The optical element is formed, for example, essentially from polythiourethane, polymethyl methacrylate, polymethyl acrylate, polycarbonate, polyacrylate, or polydiethylene glycol bisallyl carbonate, although other transparent plastic materials can also be used. In particular, it is preferred that the optical element is formed essentially from an acrylate polymer, such as polymethyl methacrylate or polymethyl acrylate. The optical element can be formed with, at least in some regions, substantially planar surfaces and / or with, at least in some regions, substantially curved surfaces.

[0030] The optical element may already have one or more functional layers. Suitable functional layers include, for example, a primer coating to increase fracture strength, a hard coating to increase scratch resistance, a non-stick or easy-to-clean layer, a conductive layer to improve antistatic properties, a reflective layer or multi-layer reflective coating, an anti-reflective layer or multi-layer anti-reflective coating, a dye layer, etc.

[0031] The optical element can, in particular with regard to its later use as a lens or ophthalmic lens, be provided in a (raw) round form or can already have been ground or edged, which is understood to mean that the element has already undergone a process step of edge forming or edge processing and is no longer in a (raw) round form, but has a different predetermined shape, in particular a different predetermined shape due to its later use as a lens or ophthalmic lens.

[0032] Preferably, the optical element to be provided in the first method step comprises a silicon oxide layer arranged directly or indirectly on a surface of the optical element. The surface of the optical element or the optical lens is thereby advantageously hardened, but in particular also prepared for a covalent bond with an omniphobic layer that is or will be formed on the silicon oxide layer.

[0033] In a further development, the step of providing the optical element comprises arranging the optical element on a suitable holding device, preferably on a holding device of a (semi- or partially) automated displacement unit, which is particularly suitable for carrying out the immersion and removal described in the following steps in an optionally computer-controlled, (semi- or partially) automated form, ie in this further development, the method according to the invention can also be implemented or carried out as a (semi- or partially) automated method.

[0034] The second method step, which follows the first method step, involves immersing the optical element in a bath. In this method step, the optical element prepared in the previous method step is immersed in a bath. In this method step, the optical element is preferably immersed in the bath in such a way that the optical element is completely surrounded by the liquid in the bath.

[0035] The immersion preferably takes place in a uniform movement, preferably this movement has a speed of less than or equal to 1.0 mm / s, particularly preferably less than or equal to 0.5 mm / s.

[0036] The bath essentially comprises water, preferably demineralized or deionized water, more preferably reverse osmosis water, and most preferably ultrapure water. Essentially, this means that the liquid in the bath contains or can contain water as its main component and, depending on the pH value of the bath, possibly acid(s) and / or alkali(s) for adjusting or regulating a (pre-)determined pH value as secondary component(s).

[0037] The bath is characterized in that a film is arranged or formed at the air-water interface of the bath, which film comprises at least the molecules forming the omniphobic layer. The preferably organosilicon compound is preferably arranged in an ordered manner in this film located at the interface, and the preferably hydrophobic tail group points away from or is oriented away from the water surface, while the hydrophilic head group points toward or is oriented toward the water surface.

[0038] In a further development of this, particularly before the removal or immersion step, the film located on the water surface is pushed together or compressed, preferably using a so-called film balance in a device provided or suitable for this purpose. This compresses or arranges the molecules in the film or those forming the film as much as possible, advantageously resulting in a preferentially arranged formation of the omniphobic layer, since these molecules are thus arranged in a row and orderly fashion. In particular, the areal density of the molecules is kept constant.

[0039] In the next process step, the optical element is removed from the bath or immersed in the bath, whereby the omniphobic layer is formed on the optical element, particularly during the removal or immersion process. The removal or immersion process preferably takes place in a uniform movement, preferably at a speed of less than or equal to 1.0 mm / s, particularly preferably less than or equal to 0.5 mm / s.

[0040] During the immersion or during the immersion movement, the optical element is pulled through, moved through, or passes through the film arranged at the air-water interface of the bath. Because the molecules of the organosilicon compound are arranged in an orderly fashion in this film, a directed or ordered bond to the optical element advantageously occurs, and the molecules preferably bind to the optical element via their head group, with the opposite functional group or tail group, which has hydrophobic properties, pointing away from the optical element, thereby imparting a water-repellent effect.

[0041] Because, in a preferred development, the film is pushed together and the molecules of the organosilicon compound are thus arranged as closely as possible in this film, the optical element is covered as completely as possible with the molecules of the organosilicon compound during immersion, ie the formation of the omniphobic layer takes place as completely as possible, whereby very good omniphobic properties are advantageously obtained.

[0042] The proposed method describes the formation of the omniphobic layer by immersion in a bath, i.e. the optical element to be provided with an omniphobic layer is immersed in a bath (and removed again) during the method, whereby the omniphobic layer is formed on the optical element. The formation of the omniphobic layer takes place in two steps: the first reaction step, the hydrolysis of the (hydrolyzable) organosilicon compounds, can take place in the bath or when passing through or emerging from the film layer, whereas the bonding, in particular covalent bonding, of the organosilicon compound takes place in the second reaction step, the condensation. The condensation step should take place on the optical element in order to ensure the most ordered transfer and thus the most ordered bonding of the molecules to form a particularly omniphobic layer.The condensation reaction should be prevented from occurring in the film layer, located at the air-water interface of the water bath, with the formation of lateral bonds or cross-links between adjacent molecules of the organosilicon compound, which would lead to the formation of larger units, in order not to destroy the perfect order. For particularly good omniphobic properties, the molecules of the organosilicon compound must be present in an ordered form in the film layer and transferred to the surface of the optical element in this way. The goal is to achieve the desired reaction behavior by appropriately selecting the pH value of the water bath, particularly depending on the selected organosilicon compound.

[0043] The bath is characterized in that it has a pH value between about 3.0 and about 6.0, preferably between about 3.5 and about 5.5, particularly preferably between about 4.0 and about 5.0.

[0044] These details are to be understood in such a way that a value between A and B means that the value is greater than or equal to A and (simultaneously) less than or equal to B. The pH value of the bath is set at the beginning of the process or, in further development thereof, monitored, in particular continuously monitored, and in further development, in particular during the process, actively monitored and, if necessary, readjusted or adjusted, preferably by appropriately adding a pH-regulating substance in order to ensure a constant pH value of the bath during the process.

[0045] The invention has recognized that by adjusting or regulating the pH value of the bath, the reaction, in particular the reaction steps of hydrolysis and in particular the condensation (reaction) for binding involved in the formation of the omniphobic layer, can be specifically influenced, since these reactions or their reaction rates depend on the pH value of the bath or are influenced by it.

[0046] A suitable pH value can ensure that the hydrophilic head groups of the compounds forming the omniphobic layer at the air-water interface do not enter into any unwanted reactions, as the pH value influences the onset of the hydrolysis reaction and, in particular, the condensation reaction. It has been shown that under acidic conditions, the hydrolysis reaction occurs faster than the condensation reaction. Furthermore, the condensation reaction exhibits a minimum reaction rate under weakly acidic conditions. By regulating, adjusting, or controlling the pH value, the hydrolysis reaction can be reduced.By actively adjusting the pH value of the bath, the reaction rates of the hydrolysis and condensation reaction can be influenced, in particular positively, and in this way it can be ensured that no premature reaction of individual molecules, in particular among each other, takes place in the film located on the water surface, since such a reaction would, on the one hand, disturb the highly ordered structure and, on the other hand, in particular as a consequence thereof, result in poorer bonding to the optical element, which in turn would lead to poorer surface coverage and thus to impaired omniphobic properties.

[0047] The hydrolysis of the alkoxy groups can, but does not necessarily, take place in a water bath. If it takes place in a water bath, the subsequent condensation reaction to bond the hydrolyzed alkylsilane (also called silanol) via the OH groups of the optical element can proceed more quickly. The condensation of the silanol should never take place in a water bath. This would cause neighboring molecules on the water surface to crosslink laterally and form larger units, which could impair the perfect alignment when the optical element is removed from the water bath. Pragmatically, the pH value should be adjusted to ensure the best possible bond to the optical element after it has been removed from the water bath, thus achieving the best possible omniphobic properties.

[0048] The selection of the appropriate pH value is therefore always subject to the proviso that, by adjusting the pH value, conditions—preferably acidic, preferably weakly acidic—are created in the bath to prevent the unwanted onset of the condensation reaction due to the acidic conditions, thereby slowing the reaction rate accordingly. The particularly preferred pH value for optimal conditions depends on various factors, in particular the organosilicon compound contained in the film and also the temperature of the bath.

[0049] The hydrolysis rate of an organosilicon compound containing trialkoxy groups as anchor groups, hence also referred to as alkoxysilane, decreases with the length of the trialkoxy group, i.e. trimethoxy groups, for example, hydrolyze faster than triethoxy groups. Condensation requires hydrolysis, but hydrolysis does not have to have already taken place completely. Hydrolysis and condensation can also occur in parallel. For the subsequent condensation reaction, it is irrelevant whether the hydrolyzed organosilicon compound originally had a methoxy or an ethoxy group as an anchor group. The aim is to prevent partially hydrolyzed alkoxysilanes from condensing, especially while still in the bath, i.e. the condensation rate should be much lower than the hydrolysis rate. The choice of a suitable orThe pH of the bath is adjusted with particular care to prevent condensation. The condensation rate generally reaches a minimum at a pH between approximately 4.0 and approximately 5.0, which is why an optimal pH range is between approximately 3.0 and approximately 6.0.

[0050] To ensure that the alkoxysilane is as completely hydrolyzed as a silanol before the condensation reaction begins, the hydrolysis should be accelerated within the specified pH range of the bath. For a pH between approximately 4.0 and approximately 5.0, the hydrolysis rate decreases with increasing pH. Methoxy groups react faster than ethoxy groups, i.e. for methoxy groups the reaction rate of the hydrolysis reaction is faster under the same reaction conditions such as pH and temperature. For ethoxy groups the pH of the bath should therefore preferably be lower in order to accelerate the hydrolysis reaction. It follows that in particular for alkoxysilanes containing methoxy groups as hydrolyzable anchor groups the optimal pH of the bath is approximately 5.0 and for alkoxysilanes containing ethoxy groups as hydrolyzable anchor groups the optimal pH of the bath is approximately 4.0.The bath preferably has a temperature of less than about 75 °C, more preferably a temperature of less than or equal to about 50 °C, particularly preferably the bath has a temperature of about room temperature, i.e. a temperature of about 20 °C. By means of a correspondingly low temperature, on the one hand, (irreversible) damage to the optical element during immersion can be avoided, since optical elements made of a plastic base material in particular have a comparatively low heat resistance, i.e. they lose their mechanical strength in particular at excessively high temperatures, and on the other hand, the low temperature can reduce the probability of the unwanted occurrence of a premature condensation reaction.

[0051] The pH of the bath is preferably regulated by the preferably metered addition of a pH-regulating substance, particularly an acidic substance, in particular an acidic liquid or solution. All common inorganic and organic acids are suitable for this purpose, with hydrochloric acid (HCl) and / or sulfuric acid (H2SO4) being preferred. This allows the pH of the bath to be adjusted or regulated particularly easily by metered addition.

[0052] Preferably, particularly alternatively or in addition to the above-suggested regulation of the pH of the bath by means of or via an acid, the pH of the bath is regulated by a preferably metered addition of a pH-regulating, particularly preferably basic substance, in particular a basic liquid or solution. All common inorganic and organic alkalis are suitable for this purpose, with sodium hydroxide solution (NaOH) being preferred. This allows the pH of the bath to be adjusted or regulated particularly easily by metered addition.

[0053] In particular, the combination of regulating the pH value of the bath by adding an acidic and a basic substance advantageously allows for a control circuit, preferably automated in a further development, in which regulation is possible by adding a corresponding substance both when a (pre-)determined pH value of the bath is undershot and when it is exceeded.

[0054] Preferably, a lens, preferably a spectacle lens, is provided as the optical element. By providing a lens or a spectacle lens, the method is particularly suitable for forming an omniphobic layer on a spectacle lens.

[0055] Preferably, a ground or shaped-edged lens or spectacle lens is provided as the optical element. This is understood to mean a lens or spectacle lens which has already undergone a process step of shaped edging or edge processing and is no longer in a (raw) round shape, but has a different shape, in particular a predetermined shape which deviates from this, due to its later use as a lens or spectacle lens. As a result of this, and in particular as a deviation from the otherwise well-known process design in which a lens or spectacle lens is first provided with an omniphobic layer before the shaped edging process takes place downstream, a particularly smooth, omniphobic layer can advantageously be formed, since smoothness is generally a limiting factor for the shaped edging process in which the lens or spectacle lens isthe spectacle lens is held firmly and, if possible, must not or should not slip out of the holder, particularly under the forces acting during edging or edge processing, in order to avoid any (untolerable) deviations, in particular no deviation with regard to the desired optical parameters or, in the case of a spectacle lens, the ophthalmic prescription. If the lens or spectacle lens is ground or edged before carrying out the method according to the invention, an omniphobic layer with excellent omniphobic properties can advantageously be formed within the scope of the method, since the formation of the omniphobic layer represents the last treatment step in the manufacturing process of a lens or spectacle lens and preferably no mechanical process steps, in particular precisely no edging, are (still) carried out afterwards.

[0056] Preferably, the at least one organosilicon compound of the omniphobic layer has at least one alkoxy group as a head group, preferably several, particularly preferably exactly three alkoxy groups. A higher number of alkoxy groups as head groups allows for improved bonding to the optical element. Preferably, the alkoxy group(s) of the at least one organosilicon compound of the omniphobic layer is / are propoxy groups, more preferably methoxy groups, and particularly preferably ethoxy groups.

[0057] Preferably, the at least one organosilicon compound of the omniphobic layer has, as a tail group, at least one, in particular linear, alkyl or alkoxy chain having a length of at least 4 carbon atoms. With increasing chain length, the omniphobic, in particular the hydrophobic, properties increase, which is why a chain length of greater than or equal to 8, particularly preferably greater than or equal to 11, in particular a chain length of 16 or 18, is suitable for an omniphobic layer with very good omniphobic properties, wherein the chain length is always based on the number of carbon atoms contained therein. The omniphobic layer particularly preferably comprises hexadecyltriethoxysilane with a chain length of C16 and / or octadecyltriethoxysilane with a chain length of C18.

[0058] Preferably, the at least one organosilicon compound of the omniphobic layer has two, more preferably three, alkyl or alkoxy chains as a tail group, which are in particular substantially linear. This allows further improved omniphobic properties to be obtained. Particularly preferably, the omniphobic layer comprises a compound selected from the group of dialkyldialkoxysilanes and / or a compound selected from the group of trialkylalkoxysilanes.

[0059] Preferably, the omniphobic layer is formed from hexadecyltrimethoxysilane as the preferred organosilicon compound, wherein the compound is present or arranged as a film layer on a bath, in particular a water bath, and the pH of the bath is between about 3.0 and about 6.0, preferably between about 3.5 and about 5.5, in particular about 5.0. Advantageously, this can, on the one hand, ensure a preferably complete hydrolysis of the alkoxysilane, and, on the other hand, delay or prevent the onset of the condensation reaction in the film layer.slowed down, in particular prevented, so that the transfer to the optical element is as orderly as possible, the condensation reaction preferably only starting on the optical element, which leads to particularly pronounced omniphobic properties due to the ordered transfer and is characterized by the high order by a contact angle with respect to water of preferably at least about 105° and with respect to hexadecane of preferably at least about 40°. As a result, an optical element is provided with an omniphobic layer or an omniphobic layer is formed on the optical element from the organosilicon compound hexadecyltrimethoxysilane as the starting product, which is characterized by excellent omniphobic properties.

[0060] The omniphobic layer is preferably formed from hexadecyltriethoxysilane as the preferred organosilicon compound, wherein the compound is present or arranged as a film layer on a bath, in particular a water bath, and the pH of the bath is between about 3.0 and about 6.0, preferably between about 3.5 and about 5.5, in particular about 4.0. Advantageously, the preferably acidic environment can, on the one hand, ensure a, preferably complete, hydrolysis of the alkoxysilane, wherein a somewhat lower pH is deliberately set for the ethoxy group(s) to accelerate the hydrolysis reaction. On the other hand, the onset of the condensation reaction in the film layer can be delayed orslowed down, in particular prevented, so that the transfer to the optical element is as orderly as possible, the condensation reaction preferably only starting on the optical element, which leads to particularly pronounced omniphobic properties due to the ordered transfer and is characterized by the high order by a contact angle with respect to water of preferably at least about 105° and with respect to hexadecane of preferably at least about 40°. As a result, an optical element is provided with an omniphobic layer or an omniphobic layer is formed on the optical element from the organosilicon compound hexadecyltriethoxysilane as the starting product, which is characterized by excellent omniphobic properties.

[0061] Preferably, the method step of providing the optical element comprises forming or applying a layer of silicon oxide on at least one area or surface of the optical element, in particular if the provided optical element does not have such a layer, at least on one area or surface, in particular as the last or outermost layer. The silicon oxide layer can be formed by evaporating silicon monoxide (SiO), silicon dioxide and / or silicon or a mixture thereof in a PVD process under vacuum, whereby monomolecular SiO is formed in the gas phase (hence the term PVD process for physical vapor deposition) and deposited in a thin layer on the optical element, for example the optical lenses.Depending on the oxygen partial pressure set during the process, the silicon oxide layer is deposited as silicon monoxide (SiO), low-valent silicon oxide (e.g., Si2O3), silicon dioxide (SiO2), or as a mixture of two or three of the aforementioned materials. The surface of the optical element or optical lens is thereby advantageously hardened, but in particular also prepared for a covalent bond with an omniphobic layer that is or will be formed on the silicon oxide layer. Further preferably, a silicon oxide layer is formed having a physical layer thickness of greater than or equal to approximately 1 nm and less than or equal to approximately 150 nm, particularly preferably greater than or equal to approximately 20 nm and less than or equal to approximately 100 nm.

[0062] The method step of providing the optical element preferably comprises pretreatment, preferably activation, particularly preferably activation by means of a plasma and / or ion treatment, in particular for the formation of reactivated OH groups. This results in the formation or provision of reactive OH groups for the condensation of a hydrolyzed organosilicon compound. This forms covalent bonds between the omniphobic layer and the optical element. Typically, a plasma and / or ion treatment using a noble gas such as argon or krypton can be used for this purpose, although combinations thereof or reactive combinations such as an argon-oxygen plasma or a pure oxygen plasma would also be conceivable. The plasma can consist of charged particles but also partly of neutral, yet excited particles such as excited atomic oxygen or excited molecular oxygen.The plasma can also contain nitrogen or hydrogen, for example.

[0063] Particularly preferred is the combination of optionally providing an optical element having at least one area or surface on which a silicon oxide layer is arranged, directly or indirectly, or the preferred further development of a method step of forming such a silicon oxide layer, with the step of carrying out a pretreatment, in particular a pretreatment for activation, preferably for the formation of reactive OH groups. An optical element having such a silicon oxide layer in combination with the formation of reactive OH groups can create excellent conditions for the bonding of the omniphobic layer.

[0064] The method further comprises a step of drying or annealing the optical element. Here, the optical element is subjected to a heat treatment in order to achieve or enable or ensure polymerization or polycondensation of the applied or formed omniphobic layer. Annealing takes place at a temperature of less than 100°C, preferably at a temperature of less than 75°C, particularly preferably at a temperature of less than or equal to 50°C. By using a correspondingly low temperature, irreversible damage to the optical element during annealing can be avoided, since, on the one hand, optical elements made of a plastic base material have a comparatively low heat resistance, i.e.they lose their mechanical strength at temperatures that are too high, and on the other hand, optical elements having a coating, for example a (particularly multi-layer) anti-reflective or mirror-coating coating, tend to form layer cracks at temperatures that are too high due to different thermal expansion coefficients.

[0065] Preferably, such a drying or tempering step takes place for a duration of at least about 15 minutes and at most about 4 hours. If the tempering step is too short, the heat input is too low to have any effect, particularly at comparatively low temperatures as explained above, and longer durations have a saturation effect, i.e. no improved degree of drying, condensation or polymerization can be observed, and secondly they make the process uneconomical. More preferably, the duration of such a tempering step is at least about 30 minutes and at most about 3 hours, particularly preferably the duration is about 1 to about 2 hours. This can ensure, on the one hand, a sufficient degree of drying, condensation or polymerization and, on the other hand, an economical implementation of the process.

[0066] A further aspect of the present invention relates to an optical element, preferably a lens, more preferably an ophthalmic lens, particularly preferably a spectacle lens, comprising a monolayer of an omniphobic layer, in particular comprising a monolayer of an omniphobic layer formed according to one aspect of the invention, wherein the omniphobic layer comprises at least one organosilicon compound. This advantageously results in an optical element which has a particularly PFAS-free omniphobic layer and thus offers high environmental compatibility.

[0067] However, the object is not limited to ophthalmic lenses and can be any transparent or optical object to which a coating can be applied. Specific examples include glasses such as crown glass, mineral glass, window glass, flat glass, windshields, or viewing windows; elements of optical sensors, light sources, or photographic lenses; and plastics such as polyacrylates or ceramics.

[0068] The optical element preferably consists of a transparent plastic, for example a transparent plastic substrate, which can be treated or untreated. The optical element is formed, for example, essentially from polythiourethane, polymethyl methacrylate, polymethyl acrylate, polycarbonate, polyacrylate, or polydiethylene glycol bisallyl carbonate, although other transparent plastic materials can also be used. In particular, it is preferred that the optical element is formed essentially from an acrylate polymer, such as polymethyl methacrylate or polymethyl acrylate. The optical element can be formed with, at least in some regions, substantially planar surfaces and / or with, at least in some regions, substantially curved surfaces.

[0069] Organosilicon compounds exhibit omniphobic properties, particularly when their alkyl or alkoxy chain has a length of at least 4 carbon atoms, but are also particularly PFAS-free and therefore characterized by greater environmental compatibility. The omniphobic layer particularly preferably comprises hexadecyltriethoxysilane and / or octadecyltriethoxysilane as the organosilicon compound. This allows an optical element to be provided with an omniphobic layer that exhibits very good omniphobic properties, preferably a contact angle with water of greater than or equal to approximately 105° and / or a contact angle with hexadecane of greater than or equal to approximately 40°.

[0070] The optical element preferably has further, in particular functional, layers arranged between the surface of the optical element and the omniphobic layer. The optical element preferably has a buffer lacquer layer, a hard lacquer layer, and / or a (multilayer) anti-reflective or mirror coating as a functional layer. The optical element can optionally be transparent, semi-transparent, colored, in particular permanently colored, and / or provided with a photochromic coloration.

[0071] A further aspect of the invention relates to a device, in particular a coating device, wherein this device comprises a bath, a film or a film layer, a holding device designed to receive an optical element, a compression unit, a control device, a temperature control device, a pH sensor, an acid reservoir and / or an alkali reservoir and a replenishment device.

[0072] Preferably, the device is designed to carry out a method according to a preceding aspect of the invention. In this way, an optical element can be provided with an omniphobic layer in a particularly advantageous manner using the device according to the invention.

[0073] Embodiments of the invention are described in more detail below with reference to the figures. It is understood that the present invention is not limited to the embodiments shown in the figures, and that individual features of different embodiments can be combined to form further embodiments within the scope of the appended claims. Like reference numerals indicate like or recurring elements. They show: - Fig. 1 is a schematic drawing of a first embodiment of the method according to one aspect of the invention; - Fig. 2 a schematic drawing of a further development of the method from Fig. 1 comprising optional process steps which are drawn in dashed outlines; - Fig. 3 shows a section of an embodiment of an optical element, in particular produced by a method according to one aspect of the invention; - Fig. 4 shows a section of an embodiment of a device according to an aspect of the invention; - Fig. 5 a schematic representation of an organosilicon compound.

[0074] The Fig. 1 shows a schematic drawing of a first embodiment of the method according to one aspect of the invention. In a first step S100, the optical element 2 to be provided with an omniphobic layer 6 is first provided. Preferably, a plastic spectacle lens, particularly preferably made of polythiourethane with a refractive index of approximately 1.6 at a wavelength of approximately 550 nm, is provided as an optical element 2. The optical element 2 can already have functional layers 3, in particular coating or finishing coatings familiar to those skilled in the art. It preferably has a buffer lacquer layer to increase or improve the fracture strength, and / or a hard lacquer layer to increase the scratch resistance, and / or a, in particular multi-layer, coating or anti-reflective coating, the latter being designed in particular as an outermost orThe last layer comprises a silicon oxide layer 4, preferably a silicon dioxide layer. According to a further preferred embodiment, a pre-ground or pre-shaped spectacle lens is provided.

[0075] In a next step S110, the provided optical element 2 is immersed in a bath which essentially comprises a water bath and a film 12 formed or arranged at the air-water interface, comprising a compound 8 forming the omniphobic layer 6, preferably hexadecyltriethoxysilane. The provided optical element 2 is completely immersed in the bath, i.e., at the end of the process step, it is completely surrounded by the solution or water in the bath. In a preferred embodiment, the bath itself comprises ultrapure water with a temperature of approximately 22°C and a pH of approximately 4.0, wherein the pH was adjusted by appropriate addition of hydrochloric acid, or in a further development thereof, is regulated by targeted (continuous) addition, in a further development thereof, is regulated by targeted addition of an acid and / or an alkali.

[0076] In a next step S120, the optical element 2 is withdrawn or immersed from the bath. During this immersion process S120, the optical element 2 is particularly passed through or moved through the film layer 12 formed at the air-water interface, comprising, in particular, hexadecyltriethoxysilane as the preferred organosilicon compound 8 for forming the omniphobic layer 6. The pH of the bath is precisely adjusted to prevent unwanted reactions, in particular unwanted condensation (reaction), of the hexadecyltriethoxysilane molecules 8 among themselves, and the condensation (reaction) only begins after the optical element 2 has been withdrawn or moved through the film layer 12.As a result, the hexadecyltriethoxysilane molecules 8 located in the film layer 12, which are arranged in a particularly highly ordered manner, bind, in particular again in a highly ordered manner, to the optical element 2 or in particular to the silicon oxide layer 4 arranged on this element, forming the omniphobic layer 6. Due to the highly ordered arrangement of the hexadecyltriethoxysilane molecules 8 in the film layer 12, their order can be largely transferred upon bonding to the optical element, ie the existing ordered arrangement is transferred during the hydrolysis or condensation reaction, bonding to the optical element 2, whereby the omniphobic layer 6 is advantageously formed on the optical element 2 in a particularly ordered form, whereby excellent omniphobic properties are obtained.

[0077] In a further development thereof, the film layer 12 can advantageously be compressed or pushed together by means of a film scale 40 as a preferred means for compression during the immersion S120 in order to ensure a constant areal density of the hexadecyltriethoxysilane molecules 8 in the film layer 12.

[0078] After the immersion step S120, an omniphobic layer is formed on the provided optical element 2.

[0079] Fig. 2 shows a schematic drawing of a further development of the method from Fig. 1 comprising optional process steps, which are shown in dashed lines. Regarding process steps S100, S110, and S120, reference is made to the preceding paragraphs of the description.

[0080] In this development, step S100 includes, as an optional step, step S101, in which the provided optical element 2 is first provided with a silicon oxide layer 4, preferably with a silicon dioxide layer. For this purpose, a silicon (di)oxide layer is first formed on the optical element 2 provided in step S100, preferably by sputtering or physical vapor deposition, particularly preferably in a (vacuum) coating system provided for this purpose and familiar to those skilled in the art. This method step requires the formation or indirect arrangement of a silicon (di)oxide layer on at least one area or surface of the optical element 2.Preferably, a silicon dioxide layer having a physical layer thickness of at least about 1 nm, preferably having a layer thickness of greater than or equal to about 10 nm and less than or equal to about 150 nm, particularly preferably having a layer thickness of greater than or equal to about 20 and less than or equal to about 100 nm, is formed, wherein the optical element 2 is preferably arranged for this purpose in a vacuum coating system and at a pressure of less than or equal to about 2 × 10. -5 mbar in this system, a disc or a granulate of silicon dioxide is evaporated by means of an electron beam and this vapor deposit is deposited on the optical element 2 to form the silicon dioxide layer 4.

[0081] In a further development, the method comprises the optional step S102, in which a plasma treatment takes place as a preferred pretreatment of the provided optical element 2, in particular a plasma treatment of a silicon oxide layer 4 arranged directly or indirectly on the optical element 2, formed in a possible development in a preceding step S101, to form reactive OH groups. This forms reactive OH groups as potential reaction partners, in particular for the condensation of a hydrolyzed organosilicon compound for bonding the omniphobic layer.

[0082] As in Fig. 2, the optional steps S101 and S102 can be carried out either in combination, ie first step S101 and then step S102, or individually, ie only step S101 or only step S102.

[0083] In a further development, the method is expanded by a step S130, a drying or annealing step of the optical element 2. In this step S130, the optical element 2 is subjected to a heat treatment, for example by targeted irradiation with IR radiation or a residence time in a designated drying or annealing oven. Such a drying or annealing step serves to evaporate any residual water in the formed layer and in particular to accelerate the condensation reaction for the complete bonding of the formed omniphobic layer to the optical element and, if appropriate, for the formation of bonds between the individual molecules. Such an annealing step preferably takes place for a duration of approximately 45 minutes at a temperature of approximately 50°C.

[0084] The Fig. Figure 3 shows a section of an embodiment of an optical element, in particular manufactured using a method according to one aspect of the invention. An optical element 2 comprises a silicon oxide layer 4 and an omniphobic layer 6 formed thereon.

[0085] In the embodiment shown, the optical element 2 is designed as an ophthalmic lens or as a semi-finished spectacle lens 2. As a rule, transparent plastic substrates are used for this purpose, which can be formed, for example, essentially from polythiourethane, polymethyl methacrylate, polymethyl acrylate, polycarbonate, polyacrylate, or polydiethylene glycol bisallyl carbonate.

[0086] The optical element 2 of the embodiment shown is already provided with at least one functional layer 3, for example with a primer coating, a hard layer, a conductive layer, an anti-reflective layer, a coloring layer, a photochromic layer or a combination thereof, etc.

[0087] The optical element 2 was further provided with a silicon oxide layer 4, in particular made of silicon dioxide, which, in the preferred embodiment shown, is arranged indirectly, in this case by means of the functional layer 3, on the (preferably convexly curved) surface of the optical element 2. The silicon oxide layer can preferably be formed or vapor-deposited together with the functional layer 3 in a PVD process within a system. Advantageously, this allows the silicon oxide layer to be produced in a simple manner within the normal manufacturing process for spectacle lenses.To improve the adhesion of the omniphobic layer, after the application of the silicon oxide layer 4, a plasma treatment with a pure argon plasma at an argon flow of 10 sscm and a bias voltage of 120 V for a duration of 90 s is carried out for the purpose of forming reactive OH groups on the surface of the silicon oxide layer 4 for the condensation of a hydrolyzed organosilicon compound for the bonding of the omniphobic layer 6.

[0088] The omniphobic layer 6 is formed by immersing the optical element 2, which is provided with a functional layer 3 and a silicon oxide layer 4, in a bath as part of a method proposed according to another aspect of the invention. This bath contained, particularly at the air-water interface, a film comprising hexadecyltriethoxysilane 8 as the preferred organosilicon compound for forming the omniphobic layer 6. In particular, by passing through this film layer, the omniphobic layer 6, comprising hexadecyltriethoxysilane 8, was formed on the optical element 2. Hexadecyltriethoxysilane 8 was present in this film layer in a highly ordered arrangement, which was transferred to the immersed optical element 2 by the method according to another aspect of the invention, so that the omniphobic layer was formed on the optical element 2 in a highly ordered arrangement.This achieved, on the one hand, the greatest possible coverage of at least one area or surface of the optical element 2—in this case, the silicon oxide layer 4—leading to very good omniphobic properties. On the other hand, the molecules of hexadecyltriethoxysilane 8 were bound in a directed manner to the surface, which also leads to very good omniphobic properties.

[0089] The Fig. Figure 4 shows an embodiment of a device 10, in particular a coating device, according to one aspect of the invention. The device 10 is particularly suitable for carrying out a method according to another aspect of the invention, with which an optical element 2 is provided with an omniphobic layer 6 by immersion in a bath 11.

[0090] The coating device 10 has at least one bath 11, a film or a film layer 12, a holding device 13 designed to receive an optical element 2, a film scale as a preferred compression unit 14, a control device 15, a temperature control device 16, a pH sensor 17, an acid reservoir 18 and / or a alkali reservoir 19 and a replenishment device 20, wherein the replenishment device 20 is designed in particular to provide a film or a film layer 12 of molecules of the omniphobic layer, preferably of molecules of an organosilicon compound, on the air-water interface.

[0091] With a computer as a preferred control device 15 of the coating device 10, the latter is particularly designed to carry out a method according to another aspect of the invention in an automated or at least partially automated manner.

[0092] An optical element 2 to be provided with an omniphobic layer 6 is first attached to a holding device 13 of the device.

[0093] In a further development, with a view to automated process implementation, the holding device 13 can comprise an actuator which receives control commands from the control device 15 and thus performs an immersion or withdrawal movement. In other words, the control device 15 can, via corresponding commands, lower the optical element 2 arranged on the holding device 2 for the purpose of (complete) immersion in a bath 11, as shown in this sectional drawing, here as a movement in the immersion direction R. E Likewise, an exchange movement can be carried out to remove or take out the optical element 2 arranged on the holding device 2, shown here as a movement in the exchange direction R A .

[0094] The bath 11, in which ultrapure water is provided as a preferred aqueous solution, can be heated to a selected temperature by means of a heating coil as the preferred temperature control unit 16 connected to the control device 15. A pH sensor 17 is arranged in the bath, on it, or at least fluidly connected to it, via which the pH value of the bath 11 can be determined. The pH sensor 17 is connected to the control device 15, via which the control device can monitor the pH value of the bath 11, in particular continuously. By means of an acid, preferably hydrochloric acid, located in an acid reservoir 18, the control device 15 can initiate the addition of acid from the acid reservoir 18 when a certain pH value is exceeded, thereby lowering the pH value of the bath 11.By means of a lye, preferably caustic soda, located in a lye reservoir 19, the control device 15 can initiate the addition of lye from the lye reservoir 19 when a certain pH value is undershot, thereby increasing the pH value of the bath 11. By continuously measuring the pH value using the pH sensor 17 and adding acid or lye as needed from an acid reservoir 18 or from a lye reservoir 19, the control device 15 can monitor the pH value of the bath 11 and, in particular, maintain it constant.

[0095] The control device 15 is also connected to the re-dosing device 20, which is designed to provide a, preferably monomolecular, film or film layer 12 on the surface of the bath 11 at the air-water interface.

[0096] The control device 15 is also connected to a film scale as a preferred compression unit 14, which is designed to compress the film layer 12 located at the air-water interface of the bath 11 in a suitable manner in order to thereby bring about the most ordered, preferably highly ordered, arrangement of the molecules 8 of the omniphobic layer 6 located in the film layer 12. In this case, the control device 15 issues corresponding control commands to the film scale 14, whereupon the latter performs a movement, in particular a movement substantially in a direction of movement R shown. F , which is designed to compress the film layer 12 located at the air-water interface of the bath 11 in a suitable manner in order to keep the surface density of the molecules located there constant.

[0097] For the purpose of forming an omniphobic layer 6 on an optical element 2, which is arranged on a holding device 13, the holding device 13 is first immersed in the bath 11, wherein in particular an immersion movement, essentially along the immersion direction R E , is described, preferably automated by means of an actuator which carries out the immersion movement. The actual formation of the omniphobic layer 6 takes place during the immersion, ie during the removal or immersion of the optical element 2 arranged on the holding device 13, when the optical element 2 is immersed in the immersion movement, which essentially takes place along the immersion direction R Atakes place, passes through the film layer 12 or is moved through it and in the process the polar head groups of the hexadecyltriethoxysilane (as a monolayer like on the water surface) attach to the optical element and then the condensation reaction takes place, which leads to the covalent bonding of the molecules present in the film layer 12 to the optical element 2.

[0098] The Fig.Figure 5 shows a schematic representation of hexadecyltriethoxysilane as a preferred organosilicon compound 8 for forming an omniphobic layer 6 on an optical element 2. Starting from its silicon atom 80, it has three ethoxy groups as preferred coupling groups 81 for attachment, and a sixteen-carbon alkyl chain as functional group 83, responsible for the omniphobic properties. The coupling groups 81 can also be referred to as head groups and are generally hydrolyzable groups, preferably chloro groups, more preferably methoxy groups, particularly preferably ethoxy groups, in particular alkoxy groups. The functional group 83 is also referred to as a tail group and is generally an alkyl or alkoxy chain having at least 4 carbon atoms or, in other words, having a chain length based on the carbon atoms of C4.The designations head group and tail group refer to the orientation of the hexadecyltriethoxysilane 8 during the formation of the omniphobic layer 6, in which the hexadecyltriethoxysilane 8 forms a bond with the silicon oxide layer 4 arranged on the optical element 2 by means of one of the (or several or all) head or coupling groups 81, i.e. the coupling or head groups 81 are oriented towards the optical element 2 in the preferred arrangement, whereas the tail group 83 is oriented away from the optical element 2. This, on the one hand, realizes the bond to the optical element 2 (or to the silicon oxide layer 4 arranged on the optical element 2), and on the other hand, the compound 8 with its alkyl chain of the tail group 83 can achieve the desired omniphobic effect.

[0099] In the present disclosure, "has an X" generally does not imply an exhaustive list, but is a shortened form of "has at least one X" and also includes "has two or more X" and "has Y in addition to X." The numerical values ​​indicated with "approximately" may preferably deviate by + / - 10% from the stated value, particularly preferably by + / - 5% from the stated value, particularly preferably by + / - 2% from the stated value, and in particular may be exactly the stated value. This applies to all numerical values ​​so designated in this application. The wording "essentially" means that a substance or material or compound consists for the most part of the stated substance or material, i.e.“X consists essentially of Y” means that the proportion of Y in X is in particular greater than or equal to 50%, preferably greater than or equal to 75%, particularly preferably greater than or equal to 90%, and also includes the case that X consists or is formed only of Y. List of reference symbols 2 Optical element or lens or spectacle lens 3 Functional layer 4 Silicon oxide layer 6 Omniphobic layer 8 Organosilicon compound 80 silicon atoms 81 header or anchor group(s) 83 Functional group(s) or tail group(s) 10 Device or coating device 11 bathrooms 12 Film or film layer 13 Holding device 14 Compression unit or film scale 15 Control device 16 Tempering device 17 pH sensor 18 Acid reservoir 19 Lye reservoir 20 Dosing device R A Direction of exchange or direction of the exchange movement R E Immersion direction or direction of the immersion movement R F Compression direction

Claims

[1] Method for forming, in particular a monolayer, an omniphobic layer (6) on an optical element (2) by immersion in a bath (11), comprising the steps: - Providing the optical element (S100); - Immersing the optical element in the bath (S110); - removing or submerging the optical element from the bath (S120); characterized by , that - the bath has a pH value between 3.0 and 6.0, and - a film (12) is arranged or formed at the air-water interface of the bath (11), which film has at least the molecules (8) forming the omniphobic layer (6), and - the omniphobic layer (6) comprises or is formed by at least one organosilicon compound (8), and - the method comprises, as an additional method step, the step of drying or tempering the optical element (S130), wherein the drying or tempering of the optical element takes place at a temperature of less than 100 °C, preferably at a temperature of less than 75 °C, particularly preferably at a temperature of less than or equal to 50 °C. [2] Method according to claim 1, wherein the optical element (2) is a lens, preferably a spectacle lens, particularly preferably a ground or shaped-edged spectacle lens. [3] Method according to one of the preceding claims, wherein the at least one organosilicon compound (8) has as functional group (83) a substantially linear alkyl or alkoxy chain with a C chain length of greater than or equal to 4. [4] Process according to one of the preceding claims, wherein the organosilicon compound (8) has at least one hydrolyzable group (81), preferably a chloro or methoxy group, a propoxy group, an amine, a silazane, an oxime or an acetoxy group, or an ethoxy group. [5] Method according to one of the preceding claims, wherein the omniphobic layer is formed by the organosilicon compound hexadecyltriethoxysilane or hexadecyltrimethoxysilane or octadecyltriethoxysilane or octadecyltrimethoxysilane. [6] A method according to any one of the preceding claims, wherein the bath has a temperature of less than 75°C, more preferably a temperature of less than or equal to 50°C. [7] Process according to one of the preceding claims, wherein the pH of the bath is adjusted or kept constant by adding an acid, preferably by adding hydrochloric acid or sulphuric acid, and / or by adding an alkali, preferably by adding sodium hydroxide solution. [8] Method according to one of the preceding claims, wherein the step of providing the optical element comprises at least one of the following method steps on at least one surface of the optical element: - forming a silicon oxide layer (S101); and / or - a pretreatment, preferably an activation, particularly preferably an activation by means of a plasma and / or ion treatment, in particular for the formation of reactivated OH groups (S102).

Images