Method for applying glare reducing coating to substrate, coating liquid, solar glass or solar film having coating, solar cell and / or solar module, and solar device

Abstract

The invention relates to a method for applying a glare-reducing coating to a substrate, in particular to a solar glass and / or to a solar film, in which a structured coating for refracting and / or scattering incident light is applied to the substrate, comprising the following steps: providing the substrate such that the substrate can be used for applying the coating, applying a coating liquid to the substrate such that an original layer of liquid is generated on the substrate, pre-curing the surface of the coating liquid by means of a pre-curing radiation radiated to the surface such that the surface is pre-cured and the support layer located between the surface and the substrate remains liquid and / or at least exclusively gelled, the surface forms a random microstructure as a result of the radiation of the pre-curing radiation,-curing the surface and the support layer by means of a curing radiation radiated onto a previous liquid original layer, such that a coating comprising the cured surface and the cured support layer is formed from the original layer by means of the coating liquid, such that a glare reducing coating is applied on the substrate.

Description

[0001] This invention relates to a method for applying a glare-reducing coating to a substrate, particularly a method for applying a glare-reducing coating to solar glass and / or solar films, wherein a structured coating for refracting and / or scattering incident light is applied to the substrate. Furthermore, this invention relates to a solar glass, a solar cell, and / or a solar module coated with a liquid and having such a coating with an irregular microstructure, wherein the solar cell and / or the solar module comprises solar glass, and to a solar device having multiple solar cells and / or multiple solar modules.

[0002] In particular, for photovoltaic cells, also known as solar cells, the corresponding surfaces, typically made of glass, need to be designed to reduce glare, i.e., to reduce or especially prevent the reflection of incident light, so that the solar cell can achieve the maximum possible solar energy output or high power output. Furthermore, this avoids, for example, unpleasant reflection behavior to the observer, and / or reflections related to building codes.

[0003] Known substrates, particularly solar glass and / or solar films, are pressed using uniform microstructured patterns, for example, through mold pressing or roll forming processes, resulting in a surface with such uniform structure exhibiting a significant reduction in reflected radiation emission by at least one to three orders of magnitude. This microstructure is replicated from a master, i.e., a mold or corresponding roll, or exists naturally in glass, such as rolled glass or also float glass, and—particularly configured as a film or directly as rolled glass—is then bonded, i.e., adhesively or bonded, to the front glass or another covering of the photovoltaic module. Etched glass is also known and can be used as solar glass. However, these methods are often complex and require specific tooling and typically multiple production steps. Furthermore, the achievable surface structuring is relatively coarse, for example, where the structures are on the order of millimeters or at least hundreds of micrometers. While glass modified by etching can have finer structures, the manufacturing process here is complex, and the results are, to some extent, unsatisfactory for the specific purpose of glare freedom.

[0004] US 2013 / 0129980 A1 discloses a method for generating a matte finish on a plastic substrate, wherein the substrate is coated, in particular, with respect to PMMA. In this case, an acrylate-based coating is used, and the substrate is irradiated with excimer radiation.

[0005] The paper "UV curing and matting of acrylate coatings reinforced by nano-silica and micro-corundum particles (Part 1)" (Frank Bauer, Roman Flyunt et al., 2007, Elsevier BV) describes the fabrication of matte surfaces using embedded nanoparticles. For this purpose, acrylate-based coatings were used.

[0006] The paper “UV curing and matting of acrylate nanocomposite coatings by 172 nmexcimer irradiation (Part 2)” (Frank Bauer, Ulrich Decker et al., 2008 Elsevier B.V.) also describes the fabrication of coatings from the liquid phase, in which an acrylate- and epoxy-based coating system is used.

[0007] The publication “VUV-induced micro folding of acrylate-based coatings, 2. Characterization of surface properties” (Rolf Schubert, Frank Frost et al., 2009, Elsevier BV) demonstrates the fabrication of microstructures in coatings, where high-energy light irradiation is used to generate microfolds.

[0008] US 2006 / 0019114 A1 discloses a method for generating nanostructured surface coatings.

[0009] US 2008 / 0135091 A1 describes a method for manufacturing solar panels that increase light output.

[0010] Here, known coatings are either not weather-resistant enough or do not exhibit the desired optical properties, namely low glare combined with optimized light transmission.

[0011] The purpose of this invention is to improve upon existing technologies.

[0012] This objective is achieved by a method for applying a glare-reducing coating to a substrate, particularly a method for applying a glare-reducing coating to solar glass and / or solar films, wherein a structured coating for refracting and / or scattering incident light is applied to the substrate, comprising the following steps: - Provide a substrate such that it is ready for coating application. - Apply a coating liquid to a substrate to create a liquid primordial layer on the substrate. - The surface coated with liquid is pre-cured by directing pre-curing radiation to the surface at a pre-curing dose of at least 60 mJ / cm², particularly from 60 mJ / cm² to 200 mJ / cm², particularly from 100 mJ / cm² to 200 mJ / cm², such that the surface is pre-cured and the support layer disposed between the surface and the substrate remains liquid and / or at least only gel-like, and the surface forms a random microstructure upon irradiation with pre-curing radiation at a pre-curing dose of at least 60 mJ / cm². - The surface and the support layer are cured by final curing radiation directed onto the previous liquid primordial layer, thereby forming a coating comprising the cured surface and the cured support layer from the primordial layer by the coating liquid. This allows for the application of a glare reduction coating onto the substrate.

[0013] This enables continuous, simple, and optimized application, and especially pre-curing to form a random microstructure of the corresponding coating on the substrate, without requiring complex and expensive tools. In particular, corresponding molds or structured rollers can be omitted. It should be noted that the effects according to the invention are achieved using a pre-curing dosage exceeding 60 mJ / cm². Furthermore, the pre-curing dosage can also be limited, particularly to 200 mJ / cm², in order to enable operation, for example, in an energy-efficient manner.

[0014] This requires a relatively high pre-curing dose exceeding 60 mJ / cm², particularly 60 mJ / cm² to 200 mJ / cm², and especially 100 mJ / cm² to 200 mJ / cm², to trigger frontal photopolymerization within the coating liquid, specifically by utilizing photons of their respective wavelengths to trigger frontal photopolymerization within the coating liquid. This also results in a greater crosslinking penetration depth in a short time, thereby generating structures with a desired higher aspect ratio.

[0015] In this context, gloss values ​​of <0.3 / <1.5 / <1.5 were specifically obtained at 20° / 60° / 85°. These "gloss values" were measured according to DIN EN ISO 2813 at the time of application.

[0016] The following terms are explained in this context: "A method for applying a glare-reducing coating" is a technical approach that ensures the use of a "glare-reducing coating"—a coating that actively improves reflective behavior to increase incident radiation and / or reduce back reflection—through corresponding steps. In addition to reducing actual reflection, targeted light scattering and / or deflection can also reduce back reflection by, for example, distributing or altering the angle of the outgoing light. As a measure of glare reduction, reference values ​​of up to 100,000 cd / m², up to 50,000 cd / m², or even up to 25,000 cd / m² or 10,000 cd / m² can be mentioned here, depending on the respective requirements and also on the respective angle relative to the vertical direction. The corresponding glare-reducing coating is applied to a "substrate," i.e., a solar film, solar glass, or another carrier—particularly a transparent or translucent carrier—so that the corresponding substrate can then be used to produce a solar module. For example, a correspondingly pre-treated solar film can then be applied to a solar module; however, similarly, the solar module or the covering glass of the solar module can also be directly used as a substrate and treated accordingly. In this respect, the substrate can also be formed from the solar cell itself; that is, if, for example, the additional weight of solar glass is to be avoided, the solar cell, for example, made of silicon, can be directly coated. It should be noted here that the terms "solar film" and "solar glass" in this context can refer, on the one hand, to a film made of plastic, and on the other hand, to glass suitably prepared for solar energy applications, but generally refer to a layer covering and / or protecting the solar cell, particularly a semi-transparent layer. Therefore, the method according to the invention is generally suitable for providing a corresponding glare-reducing coating for the respective semi-transparent layer covering and / or protecting the solar cell.

[0017] Here, "solar cell" typically refers to a silicon wafer used in photovoltaics, which has contact points for generating electricity. In contrast, "solar module" describes a deployable and applicable unit, such as a robustly constructed framed unit in which one or more solar cells are mounted and electrically connected. Such a solar module may also have additional electrical connections and / or switching devices, for example, to enable power feeding into the grid.

[0018] The term "structured coating" here describes a coating with corresponding protrusions and depressions in the thickness direction, thereby introducing a physical structure within the coating that is particularly suitable for refracting or scattering incident light. "Incident light" in this context describes, for example, sunlight that strikes a solar glass and / or solar film, and after refraction and / or scattering, can be used in a solar cell disposed behind the solar glass or solar film. "Refracted" incident light here describes deflected or redirected incident light, particularly in transition regions between different materials (e.g., from the environment to the solar film), while "scattered" describes the diffusion and / or particularly disordered redirection and / or deflection of incident light.

[0019] The term "providing" a substrate here describes, for example, the process of introducing the substrate into the corresponding system or workstation, such that the substrate is positioned appropriately for applying the coating. In particular, the substrate is arranged, for example, horizontally, so that the coating can be applied accordingly along the direction of gravity.

[0020] The term "apply" describes the physical application of a "coating liquid" onto a substrate. The coating liquid can be a liquid with a viscosity similar to, for example, water or varnish, or a gel-like substance. "Liquid" here refers to viscous media of varying viscosities, which are flowable or deformable, particularly having a viscosity below, for example, 100,000 mPa·s. These possible coating liquids share the characteristic of being flowable or spreadable. The result is a "liquid base layer," i.e., a layer of coating liquid (similar to a varnish layer) formed on the substrate.

[0021] It is further noted that, before or during the application of the coating liquid, adhesion on the substrate can be increased by, for example, applying a primer, chemically or physically activating the surface of the substrate, and / or by adjusting or modifying the coating liquid or equipping the coating liquid with adhesive-promoting components, thereby improving adhesion before or during application. If a primer is used, it can also undergo its own curing process before the application of the coating liquid.

[0022] "Pre-curing" describes the partial curing of the coated liquid—that is, a chemical and / or physical transformation—resulting in a significant increase in viscosity and a transformation, for example, into a solid state. In this process, the "surface"—the portion of the coated liquid facing away from the substrate and towards the environment—is pre-cured. This pre-curing is carried out by "irradiated pre-curing radiation," that is, using appropriate high-energy electromagnetic radiation suitable for and used to perform pre-curing. This pre-curing radiation can be selected from different spectral ranges of the electromagnetic spectrum and may, for example, include visible light. As a result, the surface is pre-cured, i.e., transformed into a higher viscosity state, particularly a solid state. In contrast to the surface, the "support layer" disposed between the surface and the substrate remains liquid and / or at least only gel-like, where "liquid" here describes a viscosity at least lower than that of the surface. "Gel-like" here describes the transition from a technically liquid state to a gel-like and / or solid state.

[0023] Surprisingly, when a suitable coating liquid is selected, the surface forms a “random microstructure” upon irradiation with pre-curing radiation—that is, a random and particularly irregular number of protrusions and depressions, especially within the microscopic range—allowing for the preparation of a corresponding structured surface with this random microstructure. In this regard, it should be mentioned that the typically generated microstructure has an aspect ratio of, for example, 0.1 to 0.4, wherein, for example, with corresponding irregular deviations, an oscillation frequency of about 6 times occurs within about 200 µm. Therefore, structures in the range of 5 µm to 50 µm can be generated, for example, structures in the range of about 25 µm or also about 35 µm. The amplitude of the corresponding microstructure can here be, for example, 1 µm to 5 µm. The result is a fine and delicately structured coating with significantly reduced glare.

[0024] The "aspect ratio" here is the ratio of the height to the width of the corresponding feature structure. In the case of a glare reduction coating, it is the ratio of the average height to the average width of the corresponding morphology within the measurement area.

[0025] Then, the surface and support layers are “cured,” where curing describes transforming the surface and support layers into a solid or gelled viscous medium to such an extent that it prevents the surface and support layers from flowing away and / or changing, and establishes a permanent state. The curing of the previous liquid original layer is carried out by “final curing radiation by irradiation,” that is, electromagnetic radiation specifically selected in each case, similar to the pre-curing radiation by irradiation, so that a coating comprising a cured surface and a cured support layer is formed from the original layer by the coating liquid.

[0026] The result is that a glare-reducing coating is applied to the substrate by generating random microstructures on the substrate and fixing—in particular, curing—the random microstructures.

[0027] To perform this method with particular reliability and as little technical simplicity as possible, an application of a coating liquid capable of curing by ultraviolet radiation is made. Specifically, the coating liquid comprises acrylate, acrylate groups, epoxy groups, aryl, vinyl, and / or vinyl groups, such that pre-curing and / or curing are carried out, particularly by ultraviolet radiation, and / or pre-curing and / or curing are carried out by excimer radiation and / or by electron radiation and / or by infrared radiation. For this purpose, monomers or oligomers having unsaturated compounds are particularly suitable. Additionally, the corresponding coating liquid may contain additives used, for example, to adjust the desired properties of the coating liquid or to reduce glare in the coating.

[0028] The term "ultraviolet radiation" here specifically describes the range of wavelengths in electromagnetic radiation invisible to the human eye, where the ultraviolet portion of the electromagnetic spectrum is described as ranging from approximately 380 nm to approximately 100 nm, with the corresponding boundary regions potentially blurred. It has been found, in particular, that acrylates and / or low-polyacrylates can be pre-cured and / or cured by ultraviolet radiation. Pre-curing and / or curing can also be performed by "excimer radiation," which is generated by an excimer (an abbreviation for "excited dimer"). This technique is used, for example, in excimer lasers, where short-lived particles in an excited state emit light accordingly, thereby generating light, in particular, at specific wavelengths. For example, light with a wavelength of 172 nm can be generated by a xenon excimer lamp, which can be used for pre-curing.

[0029] "Electron radiation" describes a technically generated electron beam, which can also be used for pre-curing and / or curing, depending on the appropriate selection of the coating liquid.

[0030] In one embodiment, the pre-curing radiation and / or the final curing radiation have wavelengths from 100 nm to 300 nm, particularly from 150 nm to 250 nm, and particularly from 172 nm and / or 222 nm.

[0031] To generate a structured coating suitable for photovoltaic modules, a coating liquid is applied with a layer thickness of 3 µm to 100 µm, particularly with a layer thickness of 5 µm to 35 µm, and / or applied by roller coating, spray coating, screen printing, slit spraying, and / or doctor blade application.

[0032] According to one embodiment of the invention, the coating liquid is applied at a viscosity of 0.4 Pa·s to 0.8 Pa·s. This viscosity range, particularly 0.5 Pa·s or even 0.6 Pa·s, ensures the achievement of a corresponding glare-free microstructure on the coating surface.

[0033] Here, "viscosity" describes the property of a liquid or even gaseous material system to flow under mechanical stress and undergo irreversible deformation in the process. The applied mechanical stress depends on the rate of deformation. Therefore, high viscosity describes lower fluidity relative to a material system with low viscosity. Generally, viscosity is given in Pa·s (Pascal-second).

[0034] Here, for example, the mixture of the corresponding monomers and oligomers is decisive in setting the viscosity of the coating liquid. For example, if a photoinitiator and nano silica are added additionally, a mixture of an aliphatic urethane acrylate with a functionality of 2 to 4 and a weight fraction of 25% to 40% and an acrylate with a functionality of 2 and a weight fraction of 28% to 40% can be used.

[0035] According to another embodiment of the invention, the coating liquid has SiOx, wherein the fraction of SiOx in the coating liquid is 20 wt% to 30 wt%. Such a SiOx fraction promotes a tendency for the coating liquid to form microfolds—i.e., irregular wavy shapes—and thus form a glare-free coating. This SiOx is also introduced, particularly as nanoscale SiOx.

[0036] In this context, silanization of the SiOx surface can help allow for an increase in the SiOx fraction while still maintaining a relatively low viscosity. This silanization generates a polysiloxane layer on the surface of the SiOx particles, which leads to compensation of the surface tension between the SiOx particles and the surrounding organic liquid of the coating liquid.

[0037] The term "SiOx" here specifically refers to inorganic oxides of silicon, in which silicon dioxide, also known as quartz, can be used. In particular, SiOx generated by pyrolysis can be used, especially after silanization, to achieve particle sizes typically from 2 nm to 100 nm, particularly from 10 nm to 100 nm. Such SiOx particles with these particle sizes are also generally referred to as nano-silica.

[0038] The corresponding layer thickness reliably ensures the effect of generating random microstructures as described above. "Roll coating application" here describes application, for example, by a cylindrical roller, such that, for example, in a continuous process, the substrate can be reliably coated with a coating liquid of a corresponding layer thickness. Similarly, for example, known methods for coating substrates can be used.

[0039] In another embodiment, pre-curing is carried out in an ambient atmosphere, wherein the viscosity (particularly the temporary viscosity) of the coating liquid and / or the microfolding frequency of the random microstructure of the surface are adjusted by setting the irradiation duration and / or the wavelength of the pre-curing radiation. Similarly, other parameters, such as layer thickness, selection of the coating liquid, and adjustment of the radiation intensity of the pre-curing radiation and / or the final curing radiation, can be varied to accordingly adjust the glare reduction coating.

[0040] Pre-curing in an ambient atmosphere has proven particularly reliable for generating random microstructures, where the “irradiation duration”—i.e., the corresponding irradiation time—and / or the selection of the appropriate wavelength of the pre-curing radiation can be used to shape the random microstructures as desired. During this process, the “temporary viscosity”—i.e., the viscosity of the coating liquid set during the process—and / or the “microfolding frequency”—i.e., the number of peaks and troughs on the surface, for example, within a specific reference region, such as within a defined measurement length—are configured accordingly.

[0041] In particular, final curing can be carried out under a protective atmosphere with a higher nitrogen content or a lower oxygen content compared to the ambient atmosphere. For this purpose, an atmosphere with an increased fraction of nitrogen or another non-reactive or inert gas can be used, especially to eliminate oxygen.

[0042] In this way, for example, a protective atmosphere is used to block the corresponding harmful effects, in which nitrogen has proven to be particularly reliable.

[0043] According to another embodiment, pre-curing is carried out at a pre-curing temperature of 10°C to 50°C, and more particularly, at a pre-curing temperature of 20°C to 35°C. This temperature range, especially when combined with the other embodiment, helps to achieve the microstructure according to the invention.

[0044] According to one embodiment, excimer radiation can also be used to clean, purify, and / or pretreat the substrate, particularly in an ambient air atmosphere. Here, the provided, or even increased, oxygen content can help improve the cleaning, purifying, and / or pretreatment.

[0045] In one implementation, a glare-reducing coating is applied directly to solar cells, solar glass, and / or solar modules, or to products or translucent components that surround, cover, and / or protect solar cells and / or solar modules. Examples of applications with photovoltaic elements include: car roofs, building facades, handheld electronic devices, bicycle speedometers, solar-powered mobile energy storage devices, and / or mobile data processing devices. As an example of directly coated solar cells, weight-optimized solar cells for space applications are mentioned.

[0046] This "direct application" means applying the coating liquid directly to the solar cell, substrate, solar glass, solar film, and / or solar module, thereby omitting the corresponding intermediate steps for transferring or bonding the coated elements that carry the microstructure. Here, the substrate—particularly the solar glass, solar film, and / or solar module—may have been pretreated, for example, with a primer.

[0047] In another aspect, this objective is achieved by a coating liquid for generating a glare-reducing coating on a substrate, particularly by a method according to any of the foregoing embodiments, wherein the coating liquid has acrylate, acrylate groups, epoxy groups, aryl, vinyl and / or vinyl groups and a viscosity of 0.4 Pa·s to 0.8 Pa·s.

[0048] In this regard, it should be noted that typical low-polyacrylate adhesives have relatively high viscosities, such as 10 Pa·s to 10,000 Pa·s, with a viscosity >0.8 Pa·s. The desired viscosity is achieved here by adding another component, particularly a low-viscosity reactive diluent (e.g., HDDA = hexanediol diacrylate).

[0049] According to one embodiment, the acrylate present in the coating liquid is 1,6-hexanediol diacrylate, particularly having a concentration of 10 wt% to 30 wt%. This ensures high weather resistance stability in the glare-reducing coating.

[0050] Here, "weather resistance" specifically refers to the glare-reducing coating's resistance to wear, yellowing, or clouding, with the negative effects primarily caused by light—specifically, by ultraviolet radiation under sunlight. High weather resistance here refers to sustained resistance to these negative effects.

[0051] According to one embodiment, the coating liquid has a SiOx concentration of 20 wt% to 45 wt%, particularly 20 wt% to 30 wt%, 30 wt% to 40 wt%, or 30 wt% to 45 wt%.

[0052] A glare-reducing coating is generated by means of one or more of the methods according to the invention described in the foregoing embodiments, having a profile with an amplitude of 3 µm to 10 µm, an aspect ratio between 0.1 and 0.2, and / or an oscillation frequency of 6 to 8 times per 200 µm measured length.

[0053] In another aspect, this objective is achieved by a substrate, particularly solar glass or solar film, having a coating with an irregular microstructure, wherein the coating is generated by the method according to the foregoing embodiments and / or by a coating liquid according to any of the foregoing embodiments.

[0054] "Solar glass"—especially the covering glass that can constitute a photovoltaic module—is made, for example, of glass that can be used in photovoltaic modules, wherein the solar glass here is optimized for a specific wavelength range of transmission required for solar energy output or for another optical property. "Solar film," as described above, is, for example, a film made of plastic, which is flexible and / or formable, and is typically flat and thin relative to its area. Solar glass or solar film can also be optimized for mechanical strength, for economic reasons, or for abrasion resistance.

[0055] In another aspect, this objective is achieved by solar cells and / or solar modules, wherein the solar cells and / or solar modules have solar glass and / or solar films according to the foregoing embodiments and / or the solar cells have glare reduction coatings according to the invention.

[0056] In another aspect, this objective is achieved by a solar energy device having multiple solar cells and / or multiple solar modules according to the foregoing embodiments. Such a solar energy device can generate particularly high solar energy yields by utilizing the microstructuring according to the invention—particularly the glare reduction coating with random microstructure according to the invention.

[0057] The invention will be explained in more detail below by way of exemplary embodiments. The accompanying drawings show: Figure 1 : A coating process used to coat substrates for solar energy applications; Figure 2 : Figure 1 Surface scan and schematic diagram of the structured surface of the coating; Figure 3 :about Figure 1 A schematic diagram of the back reflection function of incident light on the coating; and Figure 4 PV element with a coating having a microstructure.

[0058] Coating method 101 is used to coat substrate 103. Substrate 103 may be a thin glass layer; alternatively, substrate 103 may be formed from a film or from another suitable, particularly translucent, surface. In the example described here, it is assumed that the substrate is a thin solar glass. Such solar glass exhibits particularly high transmittance for wavelengths of light that can be converted into current by a solar cell.

[0059] Applying liquid 131 to substrate 103 in application area 106 via roller 105, with a defined layer thickness of approximately 25 μm. The coating liquid 131 is an acrylic ester with a varnish-like viscosity. It should be noted that substrate 103 moves along conveyor motion 181 during continuous feeding, i.e., it is also guided below roller 105. Pretreatment and / or aeration of the coating liquid 131 can then be performed in pretreatment area 107 adjacent to the application area along the conveyor motion. Similarly, targeted aeration, leveling, and / or conditioning of the coating liquid 131 can be performed in this pretreatment area 107, for example.

[0060] In the pretreatment region 107, the coating liquid 131 exists on the substrate 103 in the form of a liquid layer 133. Subsequently, along the transport motion 181, the substrate 103 having the liquid layer 133 passes through the surface curing region 123, in which radiation is introduced into the liquid layer 133 by the surface curing unit 109. This involves excimer radiation (pre-curing radiation) with a wavelength of 172 nm. A suitable atmosphere can be established within the pre-curing volume 153 located between the surface curing unit 109 and the liquid layer 133, for example, by purifying air. The liquid layer 133 then forms a surface 135 and a carrier layer 137, wherein the surface 135 is oriented toward the surface curing unit 109, and the carrier layer 137 forms a contact toward the substrate 103. Here, the carrier layer 137 retains the liquid, i.e., is configured similarly to the liquid layer 133, while the surface 135 undergoes initial curing due to the excimer radiation from the surface curing unit 109. In this process, surface 135 forms a random microstructure, the geometry of which (e.g., gel-like) is pre-fixed by surface curing unit 109 and supported in a floating manner on carrier layer 137. If substrate 103 is then further conveyed along transport motion 181 to final curing zone 125, surface 135 and carrier layer 137 are irradiated by final curing unit 111, wherein the final curing volume disposed between final curing unit 111 and substrate 103 may be provided, for example, with a nitrogen atmosphere to isolate, for example, atmospheric oxygen from surface 135. In this zone, surface 135 and carrier layer 137 are cured into final layer 139, thereby also fixing the microstructure of surface 135. As a result, coating 141 is formed on substrate 103, wherein the random microstructure is applied to coating 141.

[0061] Surface scan 201 illustrates this microstructuring on coating 141 in the form of a height profile. Raised regions 203 and trough regions 207 are depicted here, collectively forming microstructure 207. Again, the microstructure 207 is geometrically randomly formed, meaning that, for example, by adjusting the intensity of the surface curing unit 109, a corresponding average frequency and / or wavelength, as well as a corresponding amplitude, can be set; however, geometrically repetitive or uniform structures are not produced. Schematic 221 has an abscissa 223 and a ordinate 225, where the abscissa 223 and ordinate 225 correspond to the X / Y directions of the microstructure 207 in surface scan 201. The height function 227 represents the corresponding height evolution along a reference line about an average value 229, where the average value 229 is located at "0". Figure 2 As shown, the height function 227 is random and exhibits different local wavelengths, different amplitudes, and different valley depths.

[0062] Schematic diagram 301 has an abscissa 303 and a ordinate 305, where the abscissa 303 represents the incident angle of light to the surface of coating 141, measured from 0° to 90°, and the ordinate 305 plots the corresponding luminance in units of [cd / m²]. Function 307 shows the corresponding luminance as a function of the incident angle of light.

[0063] The PV element 401 includes a solar module 403. Embedded within the solar module 403 are solar cells 405, wherein the electricity generated by the solar cells 405 can be conducted away via a connecting cable 407. On the side facing incident sunlight 421, a covering 409 is applied, comprising a substrate 103 and a coating 141 having a microstructure 207. This microstructure significantly minimizes the reflection of incident sunlight 421, allowing more efficient radiation to reach the solar cells 405, resulting in a corresponding increase in power output and / or avoidance of unpleasant, harmful, or building-code-prohibited glare.

[0064] List of reference numerals 101 Coating Method 103 substrate 105 rolls 106 Application Area 107 Preprocessing Area 109 Surface curing unit 111 Final Curing Unit 121 Pre-curing area 123 Surface curing area 125 Final Curing Zone 131 Coating liquid 133 Liquid Layer 135 surface 137 Carrier Layer 139 Final Layer 141 Coating 153 Pre-cured volume 155 Final cured volume 181 Conveying motion 201 Surface Scan 203 Protruding Area 205 Valley District 207 Microstructure 221 Schematic Diagram 223 x-axis 225 ordinate 227 Height Function 229 Average 301 Schematic Diagram 303 x-axis 305 ordinate 307 function 401 PV element 403 Solar Module 405 solar cell 407 Connecting Cable 409 Coverings 421 Sunshine.

Claims

1. A method (101) for applying a glare-reducing coating (141) to a substrate (103), particularly a method (101) for applying a glare-reducing coating (141) to solar glass and / or a solar film, wherein, A structured coating (141) for refracting and / or scattering incident light (421) is applied to the substrate (103), the method comprising the following steps: - Provide the substrate (103) such that the substrate (103) is ready for the application of the coating (141), - Apply (106) coating liquid (131) to the substrate (103) to generate a liquid original layer (133) on the substrate (103). - The surface (135) of the coating liquid (133) is pre-cured (109) by guiding pre-curing radiation to the surface (135) at a pre-curing dose of at least 60 mJ / cm², such that the surface (135) is pre-cured and the support layer (137) disposed between the surface (135) and the substrate (103) remains liquid and / or at least only gel-like, and the surface (135) forms a random microstructure (201) by irradiation with pre-curing radiation at a pre-curing dose of at least 60 mJ / cm². - The surface (135) and the support layer (137) are cured (111) by final curing radiation directed onto the previous liquid original layer (133), thereby forming a coating (139, 141) from the original layer (133) by the coating liquid (131) comprising the cured surface (135) and the cured support layer (137). This results in a glare reduction coating (141) being applied to the substrate (103).

2. The method according to claim 1, characterized in that, The application (106) of a coating liquid (131) capable of curing by ultraviolet radiation is carried out, in particular, the coating liquid (131) comprising acrylate, acrylate groups, epoxy groups, aryl, vinyl and / or vinyl groups, such that the pre-curing (109) and / or the curing (111) are carried out, in particular, by ultraviolet radiation, and / or the pre-curing (109) and / or the curing (111) are carried out by excimer radiation and / or by electron radiation and / or by infrared radiation.

3. The method according to claim 1 or 2, characterized in that, The pre-curing radiation and / or the final curing radiation have wavelengths from 100 nm to 300 nm, particularly from 150 nm to 250 nm, and particularly from 172 nm and / or 222 nm.

4. The method according to any one of the preceding claims, characterized in that, The coating liquid (131) is applied (106) with a layer thickness of 3 µm to 100 µm, and in particular, the coating liquid (131) is applied (106) with a layer thickness of 5 µm to 35 µm; and / or the coating liquid (131) is applied (106) by roller coating (105, 106).

5. The method according to any one of the preceding claims, characterized in that, The coating liquid (131) is applied (106) at a viscosity of 0.4 Pa·s to 0.8 Pa·s.

6. The method according to any one of the preceding claims, characterized in that, The coating liquid (131) has SiOx, wherein the fraction of SiOx in the coating liquid (131) is 20 wt% to 30 wt%.

7. The method according to any one of the preceding claims, characterized in that, The pre-curing (109) is carried out in an ambient atmosphere (153) and / or in an inert gas atmosphere, wherein the viscosity (particularly the temporary viscosity) of the coating liquid (131) and / or the microfolding frequency of the random microstructure (201) of the surface (135) is adjusted by setting the irradiation duration and / or the wavelength of the pre-curing radiation.

8. The method according to any one of the preceding claims, characterized in that, The pre-curing is carried out at a pre-curing temperature of 10°C to 50°C, and in particular, the pre-curing is carried out at a pre-curing temperature of 20°C to 35°C.

9. The method according to any one of the preceding claims, characterized in that, The curing (111) is carried out in a nitrogen atmosphere (155) or in a protective atmosphere (155) with an increased nitrogen content compared to the ambient atmosphere.

10. The method according to any one of the preceding claims, characterized in that, The glare reduction coating (141) is applied (106) by directly applying it to the solar glass and / or solar module.

11. A coating liquid for forming a glare-reducing coating on a substrate, particularly, a coating liquid for forming a glare-reducing coating on a substrate by means of the method according to any one of the preceding claims, characterized in that, The coating liquid has acrylate, acrylate groups, epoxy groups, aryl, vinyl and / or vinyl groups, and a viscosity of 0.4 Pa·s to 0.8 Pa·s.

12. The coating liquid according to claim 11, characterized in that, The acrylate present in the coating liquid is 1,6-hexanediol diacrylate, and in particular, the acrylate present in the coating liquid has a concentration of 10 wt% to 30 wt%.

13. The coating liquid according to claim 11 or 12, characterized in that, The SiOx concentration is 20 wt% to 45 wt%, and more particularly, the SiOx concentration is 30 wt% to 40 wt%.

14. A solar glass (409) or solar film, said solar glass (409) or solar film having a coating (141) with an irregular microstructure (201), wherein, The coating (141) is generated by the method according to any one of claims 1 to 10 and / or by the coating liquid according to any one of claims 11 or 13.

15. A solar cell (403) and / or a solar module (401), wherein, The solar cell (403) and / or the solar module (401) have the solar glass (409) or solar film according to claim 14.

16. A solar energy device having a plurality of solar cells (403) according to claim 15 and / or a plurality of solar modules (401) according to claim 15.

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