Sheetlike glass article, preferably for solar applications, and method for the production thereof

Abstract

The present disclosure relates generally to sheetlike glass articles which can be used, for example, in solar applications as "frontside substrate", i.e. as a cover, as protection for photovoltaic modules, for example also in aerospace / outer space applications. Furthermore, the invention also relates generally to a method for producing such sheetlike glass articles and to the use thereof.

Description

[0001] SCHOTT AG 1 03.03.2026 P06334 WO

[0002] Disc-shaped glass article, preferably for solar applications, and methods for its manufacture

[0003] Description

[0004] Field of invention

[0005] The present disclosure relates generally to disc-shaped glass articles which can be used, for example, in solar applications as a so-called "front substrate," i.e., as a cover, to protect photovoltaic modules, for example also in space / outer space applications. Furthermore, the disclosure also relates generally to a method for manufacturing such disc-shaped glass articles and their use.

[0006] Background of the invention

[0007] Generally, disc-shaped glass articles, also known as glass panes or substrates, are used as covers (also called cover glasses or cover plates) for solar modules. These disc-shaped glass articles serve as protection for the photovoltaic cells they cover, for example, against mechanical stress and corrosion. At the same time, the cover glasses must also be sufficiently transparent to allow enough light to pass through them for efficient power generation.

[0008] In solar modules or solar panels for terrestrial applications, the cover sheets used can often be several millimeters thick and are frequently specially designed to enable, for example, diffuse reflection. This can be achieved, for instance, by giving the cover sheet a special rough or pyramid-shaped surface structure. Terrestrial solar modules are exposed to the elements. In contrast, cover sheets specifically designed for use in space are subject to significantly different requirements. While glass for cover sheets for terrestrial solar modules should also be as resistant to solarization as possible, these factors become even more critical in space applications. This is because, on the one hand, the radiation is significantly increased, and on the other hand, due to the SCHOTT AG 2 03.03.2026 P06334 WO

[0009] Due to the so-called payload, i.e., the transport costs into space, the cover glass should be as thin as possible. However, this presents difficulties in adjusting the cover glass material to ensure sufficient protection of the solar cells beneath it, particularly protection from harmful UV radiation, despite its minimal thickness. UV radiation can lead to the aging of the adhesive layers that connect the cover glass to the solar cells. To prevent this, components such as lead, titanium, or cerium can be added to the cover glass to improve its shielding effect against radiation, especially UV radiation. A general disadvantage, however, is that such components not only improve the shielding effect but also, of course, affect the overall properties of the glass.For example, known glasses that offer sufficient shielding often have an unfavorable, excessively high refractive index, their thermal expansion is not adequately matched to the solar module material, such as the polymer layer and / or the solar cell material, and / or the glass's melting properties do not allow for cost-effective manufacturing. In the case of lead, the additional problem is that this material increases the density of the glass—and thus the payload of the resulting cover plate—and is also toxic.

[0010] Furthermore, it is difficult to provide a glass composition which, with a very low glass thickness of around 100 m, exhibits very high spectral transmission in the visible spectrum from about 400 nm, but already has a very high blocking effect against UV radiation in the near UV around 300-350 nm.

[0011] Another requirement for cover glass for solar modules is a sufficiently high resistance to solar radiation. Many types of glass tend to experience a decrease in transmission due to the intense UV radiation found in space. This reduction in transmission must be very low for cover glass used in solar modules and must not significantly lower the efficiency of the solar modules.

[0012] Various drawing processes are known for producing suitable thin glasses from a glass melt. For glasses prone to crystallization, however, direct drawing from a SCHOTT AG 3 03.03.2026 P06334 WO

[0013] Glass melting is not always possible, as crystallization can occur during hot forming and the associated forming temperatures, i.e., during drawing. However, thin glass sheets can often still be produced from such crystallization-prone glasses using a process called cold processing. This involves casting blocks, sawing them into sheets, and, if necessary, subsequent grinding and polishing. This cold processing is characterized by high costs and a reduced quality of the glass surface, resulting from the grinding and polishing processes.

[0014] US Patent 6,207,603 B1 describes a glass suitable for covering solar cells. This glass has a sharp transmission edge and is suitable, even in very thin glass articles with a thickness between 50 pm and 500 pm, particularly at a thickness of 150 pm, to provide good protection for UV-curing materials used as adhesives between a solar cell and the cover glass, while simultaneously maintaining good overall transmission of the glass material across the wavelength range relevant to the solar spectrum. However, the glass material exhibits a relatively high coefficient of thermal expansion of approximately 7.4–10⁻⁶. 6 / K on.

[0015] The applicant's own European patent application EP 3863980 A1 mentions a broad composition range encompassing up to 3 wt.% CeO2, but does not concern glass articles, but rather glass ceramics, and is therefore very far removed from the subject matter of the present application.

[0016] Japanese patent application JP2017 / 193464 A describes a radiation-resistant glass, but for nuclear applications. Very thin, disc-shaped glass articles are not addressed; rather, thicknesses of several millimeters are described.

[0017] Japanese patent application JP 2014 / 141363 A describes a chemically temperable glass with a wide composition range, which can be used as cover glass for display applications. This glass is said to have a "blue light cut function" to prevent eye strain, thus reducing spectral transmission. SCHOTT AG 4 03.03.2026 P06334 WO

[0018] The visible spectral range is at 60% and above, but at a wavelength of 437.5 nm it is at less than 90%. However, the application concerns very thin glass articles with thicknesses of 50 mm or less.

[0019] The applicant's own German patent application DE 202023 118 163 A1 also discloses corresponding thin glasses. However, these have proven to be prone to crystallization, so that the economical production of such thin glasses using conventional drawing processes is not possible.

[0020] There is therefore a need for an improved glass material as well as for disc-shaped glass articles comprising this glass, which at least partially mitigate the aforementioned weaknesses of the prior art.

[0021] Object of the invention

[0022] The object of the invention is to provide a disc-shaped glass article, in particular for use as a cover plate, preferably as a cover plate for a solar module, especially for extraterrestrial applications, wherein the glass article, in addition to very low UV transmission and very high spectral transmission, should also be resistant to solarization and producible in the visible spectral range using conventional thin-glass drawing processes. Further aspects of the invention relate to a suitable glass from which such a disc-shaped glass article can be formed or which comprises such a glass, as well as a method for producing such a glass article. A further aspect is directed to the use of disc-shaped glass articles according to embodiments of the disclosure.

[0023] Summary of the invention SCHOTT AG 5 03.03.2026 P06334 WO

[0024] The problem is solved by the subject matter of the independent claims. Preferred and specific embodiments are found in the dependent claims of the description and the drawings of the disclosure.

[0025] The invention thus relates generally to a disc-shaped glass article, which has a thickness of 125 pm.

[0026] - exhibits a spectral transmittance of less than 3% at a wavelength of 320 nm and of at least 87% at a wavelength of 400 nm,

[0027] - wherein the disc-shaped glass article (10) comprises a cerium oxide-containing glass,

[0028] whose upper devitrification temperature (OEL) is < 1240°C, preferably < 1210°C, and / or

[0029] whose viscosity at the upper devitrification temperature T|OEG log (T|OEG / dPa-s) is > 3.3, preferably > 3.5 and more preferably > 4.0,

[0030] and optionally one of the two features:

[0031] - In the wavelength range from 500 nm to 1800 nm, the mean spectral transmission, determined as the arithmetic mean of the measured spectral transmission in this wavelength range, is at least 91%, preferably at least 92%.

[0032] - at a wavelength of 450 nm, the spectral transmission is at least 88%, preferably at least 89%, particularly preferably at least 90%.

[0033] Here, r| is the viscosity in dPa s and HOEG is the viscosity of the glass when it has the temperature corresponding to the upper devitrification temperature OEG.

[0034] Such a design is particularly advantageous. The disc-shaped glass article according to the disclosure is, as described above, designed in such a way that it already exhibits sufficient shielding against UV radiation with a very small material thickness of only 125 pm. The small material thickness is advantageous because the disc-shaped glass article is also intended for extraterrestrial applications and should therefore be as thin and thus as light as possible to avoid a high payload. SCHOTT AG 6 03.03.2026 P06334 WO

[0035] In general, glass articles with a thickness other than 125 pm can be thinned or stacked to achieve the required thickness of 125 pm to verify whether they meet the aforementioned properties. A measurement of the transmission properties can then be performed. Alternatively or additionally, mathematical calculations are possible to determine the spectral transmission of glass articles with a thickness other than 125 pm. This can be done, for example, according to the method described in the annex to DIN EN 410, starting on page 39. This method mathematically separates the transmission losses of a glass pane due to absorption within the glass and reflection at the interfaces, allowing the spectral transmission for a specific glass thickness to be converted to other glass thicknesses.A glass article according to the invention therefore does not have to have a thickness of 125 pm, but can also have different glass thicknesses.

[0036] Surprisingly, it has been shown that glasses with an OEG of < 1240°C, preferably < 1210°C and / or for whose viscosity r| at the upper devitrification temperature log (noEG / dPa-s) > 3.3, preferably > 3.5 and more preferably > 4.0 can be drawn from a glass melt using a drawing process, and consequently a particularly economical production is possible.

[0037] For the purposes of this disclosure, a glass article is generally understood to be an article or product which comprises or is formed from glass.

[0038] The upper devitrification temperature (OEG) was determined in a gradient furnace according to ASTM 0829:1981-00 "Standard Practices for Measurement of Liquidus Temperature of Glass by the Gradient Furnace Method". The glass samples were placed in platinum tubes, and the measurement was taken after melting above the expected OEG, typically between 1300 and 1600°C, for at least 30 minutes, followed by a annealing time of 16 hours in the gradient furnace. The upper devitrification temperature (OEG) [°C] corresponds to the highest temperature at which crystals still form. Above the OEG, the sample is free of crystals. SCHOTT AG 7 03.03.2026 P06334 WO

[0039] In one embodiment, the disc-shaped glass article comprises glass with a thickness of at least 30 pm and at most 175 pm, preferably at least 100 pm and at most 150 pm. Glass articles with particularly thin profiles are characterized by particularly low weight, but also exhibit lower strength and higher UV transmission. Conversely, glass articles with greater thicknesses exhibit higher mechanical strength and lower UV transmission, but are heavier.

[0040] According to one embodiment, the disc-shaped glass article comprises a glass containing SiO₂, B₂O₃, and CeO₂. In particular, this also includes an embodiment in which the disc-shaped glass article is formed from such a glass. For example, according to the present disclosure, the disc-shaped glass article can generally be understood as a glass sheet, wherein, according to one embodiment, the glass sheet is formed from a glass comprising SiO₂, B₂O₃, and CeO₂. A glass comprising SiO₂, B₂O₃, and CeO₂ can also generally be understood as cerium oxide-containing borosilicate glass.

[0041] In this description, the term glass is used not only in the literal sense, but also in the sense of a type of glass, characterized by its material composition, and therefore also refers to a glass composition.

[0042] Such a design is advantageous because the glass is initially formed as a chemically resistant glass, comprising B₂O₃ and SiO₂ as network formers. In this way, a stable glass network is formed, and the glass is therefore a borosilicate glass, thus generally belonging to the class of chemically resistant glasses. Advantageously, the glass can also contain alkalis, particularly in the form of alkali oxides.

[0043] Finally, a CeÜ2 content in the glass pane is advantageous because cerium oxide is a component that can improve the shielding effect against, for example, UV radiation and at the same time also the solarization resistance of the glass.

[0044] Preferably, according to one embodiment, the glass comprises at most 70 wt.% SiÜ2.

[0045] Preferred upper limits are 67 wt.% and 65 wt.%. A preferred lower limit for SCHOTT AG 8 03.03.2026 P06334 WO

[0046] The silicon dioxide (SiO2) content of the glass is at least 55 wt.%, preferably at least 57 wt.%, and particularly preferably at least 59 wt.%. Such a silicon dioxide content can be advantageous because the glass has a composition that allows it to melt easily, since the silicon dioxide content is limited and not too high. At the same time, however, it can also be advantageous not to reduce the silicon dioxide content of the glass too much in order to maintain the most stable glass network possible, and in particular, good chemical and / or mechanical stability.

[0047] Preferably, the glass therefore comprises at least 55 wt.% SiÜ2, preferably at least 57 wt.% SiÜ2 and, as already stated above, preferably at least 59 wt.%.

[0048] B₂O₃ is a component that generally lowers the melting point and, in combination with SiO₂, leads to the formation of chemically very resistant glasses. However, excessively high B₂O₃ contents promote segregation and should be avoided. The glass according to the present disclosure therefore comprises B₂O₃ in one embodiment, preferably at least 2 wt.% B₂O₃. For example, the glass can comprise at least 4.0 wt.% or, more preferably, at least 5 wt.% B₂O₃. Preferably, however, the B₂O₃ content of the glass is limited and, according to one embodiment, comprises at most 15 wt.%, more preferably at most 10.0 wt.%, and more preferably at most 9 wt.%.

[0049] Preferably, the glass of the disc-shaped glass article comprises these additional components in the following areas, specified as wt.% on an oxide basis:

[0050] CeO2 at least 1, preferably at least 1.5, particularly preferably at least 2 and preferably at most 4.5, preferably at most 3.5, particularly preferably at most 3.0

[0051] AI2O3 at least 0, preferably at least 2.5 and particularly preferably at least 3 and at most 14, preferably at most 10, particularly preferably at most 6,

[0052] where furthermore, it is preferred that

[0053] 3'CeO2 + Al2O3 < 17 wt.%, preferably < 15 wt.%, more preferably < 13 wt.% SCHOTT AG 9 03.03.2026 P06334 WO

[0054] CeO₂ is a component that is advantageous for providing good UV shielding and also increases solarization resistance. According to one embodiment, the CeO₂ content of the glass should therefore be at least 1.0 wt.%. Preferred minimum contents are 1.5 wt.% and 2 wt.%. Preferably, however, the CeO₂ content of the glass is limited. The following aspects are important here: Firstly, CeO₂ is a high-density component and therefore increases the payload. Furthermore, excessively high CeO₂ contents push the UV cutoff too far into the visible spectrum, and the spectral transmission at a wavelength of 400 nm decreases. According to one embodiment, the CeO₂ content of the glass is therefore at most 4.5 wt.%, preferably at most 3.5 wt.%, and particularly preferably at most 3.0 wt.%. The inventors have recognized that, depending on the other components of the glass and their proportions, even small CeO₂ contents can lead to increased crystallization or...This can lead to a tendency for the glass to deglaze.

[0055] According to one embodiment, the glass comprises Al₂O₃, preferably at least 2 wt.% Al₂O₃. Such a content is advantageous because it has been shown that this effectively prevents the separation of a glass containing SiO₂ and B₂O₃ as network formers. However, Al₂O₃ increases the melting point and simultaneously tends to reduce the chemical resistance of a glass and should therefore not be present in excessively high quantities. Preferred lower limits are 2 wt.%, more preferably 3 wt.%. It has also been shown that for the glass according to embodiments, a preferred upper limit for the Al₂O₃ content of the glass is at most 14 wt.%. Preferably, the glass comprises at most 10 wt.%, and particularly preferably at most 6 wt.%.

[0056] The inventors have discovered that, surprisingly, higher cerium oxide contents are possible in the glass even with lower AhOs concentrations, without the tendency to devitrify becoming too pronounced and rendering production using conventional thin-glass drawing processes impossible. Therefore, particularly with low AhOs concentrations, a glass that is exceptionally stable in terms of crystallization and simultaneously exhibits low solarization can be obtained. SCHOTT AG 10 03.03.2026 P06334 WO

[0057] Therefore, the following are particularly preferred for the levels of CeCh and Al2O3:

[0058] 3'CeO2 + Al2O3 < 17.0 wt.%, preferably < 15.0 wt.%, more preferably < 13.0 wt.%.

[0059] It is generally noted that, within the scope of this disclosure, the components of the glass are specified in the form in which they are usually obtained by analysis. Typically, the component is given in its stable, usually the highest, oxidation state. However, it should be noted that this does not necessarily correspond to the form in which the component actually exists in the glass. For example, iron in an oxide glass can exist in both divalent and trivalent forms, i.e., as Fe3. 2+ or FeO or as Fe 3+ or as Fe20s. The information on the levels of corresponding components within the scope of this disclosure therefore refers to usual analytical data, whereby it is understood that the component may also be present in a form deviating from the "ideal", usually specified oxidation state.

[0060] In particular, cerium oxide can also generally be considered Ce 3+ or also Ce 4+ present in the glass matrix. Regarding the discussion of the glass composition, the cerium oxide content is simplified in this description as CeO2, and the specification CeO2 thus includes both Ce 3+ as well as Ce 4+ . However, the different oxidation states of cerium will be distinguished later in this description.

[0061] According to a preferred embodiment of the disc-shaped glass article, the glass comprises less than 1.5 wt.% fluorine. It has been shown that fluorine can be used in glasses that serve as covers for solar modules, even in extraterrestrial environments. Fluorine as a component in a glass can be advantageous because it lowers the melting point of the glass. However, according to the present disclosure, it is preferred to limit the fluorine content of the glass as much as possible, since fluorine is toxic and poses problems with regard to occupational safety and environmental protection in glass manufacturing. Advantageously, the glass therefore comprises at most 1.5 wt.% or even less. In particular, according to one embodiment, the glass can even be free of fluorine except for unavoidable traces. Unavoidable traces are generally at most 500 ppm of the corresponding component, based on weight. SCHOTT AG 11 03.03.2026 P06334 WO

[0062] According to one embodiment, the glass has a coefficient of thermal expansion (GTE) in the temperature range of 20 °C to 300 °C, 020-300, of less than 7.5-10 6 / K, preferably less than 7.4-10 6 / K, especially preferred from less than 7.3-10 6 / K, especially preferred by those with less than 7.2 10 6 / K, on, for example, even less than 7.1 10 6 / K or less than 7.0-10 6 / K and especially preferably of at least 6.5-10 6 / K. The term thermal expansion coefficient is generally understood here to mean the linear thermal expansion coefficient. This can be determined, in particular, using a method according to ISO 7991. Within the scope of this disclosure, the terms expansion coefficient, (linear) thermal expansion coefficient, GTE, and 020-300 or a are used synonymously.

[0063] The coefficient of thermal expansion is an important property of the disc-shaped glass article according to the present disclosure. This is because, as explained, the disc-shaped glass article is specifically intended for use as a cover for, for example, solar cells. One material used for solar cells in this area is, for example, gallium arsenide. This material has a coefficient of thermal expansion of 6.5–10 6 / K. However, this does not usually correspond to the coefficient of thermal expansion of the resulting solar cell; rather, this coefficient is likely to be higher due to other components of a solar cell or solar module, such as metal contacts or similar. The glass should therefore have a coefficient of thermal expansion adapted to the other components of the solar cell and / or solar module, so that the overall coefficient of thermal expansion of the solar cell is not too high, but at the same time is sufficiently adapted to the materials used to prevent large thermal stresses between the module components, which can occur, for example, during the launch of a launch vehicle or later during the operation of the module.

[0064] However, known types of glass, which are already used as cover plates, usually have significantly higher coefficients of thermal expansion, for example, more than 8 or 10. 6 / K. This is unfavorable because of the difference in thermal SCHOTT AG 12 03.03.2026 P06334 WO

[0065] The coefficient of thermal expansion of the glass and other components can lead to delamination of the cover plate, i.e., a disc-shaped glass article, and the other materials of the solar module and / or solar cell.

[0066] Advantageously, the coefficient of thermal expansion of the disc-shaped glass article should therefore not exceed 7.5-10 according to one embodiment. 6 / K, preferably less than 7.4-10 - 6 / K, especially preferred less than 7.3-10 6 / K, especially preferred to less than 7.2-10 - 6 / K, for example, even less than 7.1 10 6 / K, or less than 7.0-10 6 / K and especially preferably at least 6.5-10 6 / K. The coefficient of thermal expansion of the disc-shaped glass article should also not be too low, but preferably at least 6.5 10 6The coefficient of thermal expansion (CTE) of the glass is determined to ensure good compatibility with common materials used in solar cells and solar modules. A close match of the CTE of the different materials is particularly advantageous in solar cell construction, where the glass and solar cell are bonded with adhesive (typically Dow Corning 93-500 or a similar adhesive) at 150°C (for 15 minutes). This is also beneficial in the event of rapid temperature changes in space, as it prevents warping of the solar cells and thus potential detachment from the substrate or damage to the solar cells. Providing glasses with lower CTEs can also be advantageous for the potential use of GaAs cells other than those described.Other materials for solar cells could also circumvent the disadvantage of arsenic-containing solar cells, but generally have lower coefficients of thermal expansion than the currently used glasses for cover plates of known solar modules and solar cells.

[0067] According to one embodiment of the disc-shaped glass article, the glass comprises

[0068] TiO2. Preferably the glass comprises at most 4.5 wt.% TiO2, preferably at most 1.0 wt.% TiO2, preferably at most 0.5 wt.% TiO2, particularly preferably at most 0.2 wt.% TiO2.

[0069] An embodiment of the disc-shaped glass article in the form in which the glass of the glass article comprises TiÜ2 may be particularly advantageous if the content of the glass is SCHOTT AG 13 03.03.2026 P06334 WO

[0070] The amount of CeO2 should be limited. For example, if the glass contains a relatively low proportion of CeO2 of 3 wt.% or less, it is possible to achieve cost targets in manufacturing, but this would compromise solarization resistance and, in particular, the steepness of the UV edge of the resulting glass or, correspondingly, the resulting disc-shaped glass article. The inventors have discovered that a lower CeO2 content in the glass can be compensated for by an interaction of TiO2 and CeO2, so that good solarization resistance can still be achieved even with low CeO2 contents, for example, at CeO2 contents of 3 wt.% or less.

[0071] According to one embodiment, it can generally be provided that the sum of the components TiÜ2 and CeO2 is between 2 wt.% and 6 wt.%, preferably between 2 wt.% and 5 wt.%, for example between 2 wt.% and 4 wt.% or between 2 wt.% and 3 wt.%.

[0072] It has also been shown that it can be advantageous, particularly with lower CeO2 contents in the glass, to establish a specific ratio between the TiÜ2 and CeO2 content of the glass. In particular, it can be provided that the ratio of TiÜ2 to CeO2, especially in the case of low CeO2 contents of 3 wt.% or less and / or particularly when the sum of the components is in the range between 2 wt.% and 6 wt.%, preferably between 2 wt.% and 5 wt.%, for example between 2 wt.% and 4 wt.% or between 2 wt.% and 3 wt.%, is designed such that, based on weight, the glass always contains more CeO2 than TiÜ2, or, in other words:

[0073] 0 TiO2 / CeO2 1.

[0074] Furthermore, it has been shown that the redox state of cerium in glass can be of particular importance. Cerium is an element that can exist in glass in both trivalent and tetravalent forms, for example as Ce⁻. 3+ or as Ce 4+ It has been shown that a high proportion of Ce 4+ which is advantageous in the glass of the disc-shaped glass article, because SCHOTT AG 14 03.03.2026 P06334 WO

[0075] In this way, the position and steepness of the UV edge can be adjusted. For this purpose, it can generally be advantageous to melt the glass of the glass pane under oxidizing conditions. It may be provided that the glass is melted with the addition of antimony oxide and / or nitrate and / or sulfate and / or arsenic oxide. However, arsenic oxide is not preferred due to its toxicity. In particular, it may therefore be provided that the glass of the glass pane comprises Sb₂Ü₃ up to a content of approximately 0.6 wt.%.

[0076] In general, the solarization resistance of a glass according to these embodiments, in particular a glass comprising CeO2, is very good. It has been shown that the average spectral transmission of glasses according to these embodiments in the wavelength range from 450 nm to 1800 nm is significantly reduced by irradiation for 100 hours with UV-A light at 210 W / m². 2 , with UV-B light at 170 W / m² 2 as well as UV-C light with 250 W / m² 2 The transmission changes by less than 1%. This reduction in transmission refers to a glass thickness of 125 µm. The advantageous, very high solarization resistance of the glasses or disc-shaped glass articles according to the embodiments is also shown by way of example in Table 1 below, before and after solarization.

[0077] Furthermore, it has been shown that cerium not only influences solarization resistance. As will be shown below with reference to Fig. 1, the redox ratio of cerium in the glass can have a significant influence on the position and course of the UV edge. It has been shown that the presence of cerium predominantly in the tetravalent positive oxidation state, i.e., as Ce⁻¹, is highly significant. 4+ This results in a more pronounced steepness of the UV edge and overall higher spectral transmission values.

[0078] According to one embodiment, the present disclosure therefore relates to a disc-shaped glass article comprising a glass, wherein the relative proportion of the Ce 3+ of the total cerium in the glass, determined as the sum of Ce 3+ and Ce 4+ , at most 70%, preferably at most 50% and particularly preferably at most 30%. SCHOTT AG 15 03.03.2026 P06334 WO

[0079] According to another embodiment of the disc-shaped glass article, it comprises a glass wherein the ratio of Ce 3+ to Ce 4+ in the glass 3+ / Ce 4+ , less than 2, preferably less than 1.0 and especially preferably less than 0.5.

[0080] The redox ratio of cerium in a glass is preferably determined by X-ray photoelectron spectroscopy (XPS) or alternatively by electron paramagnetic resonance (EPR).

[0081] Such a favorable redox ratio can be obtained by melting the glass in a highly oxidizing manner. This can be achieved, for example, by adding antimony oxide and / or nitrate as oxidizing agents to the molten glass, and / or by adding sulfate and / or fluorine.

[0082] According to a further embodiment of the disc-shaped glass article, the glass may contain less than 2 wt.% BaO, preferably less than 1.5 wt.% BaO, and particularly preferably less than 0.1 wt.% BaO. Barium oxide (BaO) is a component that is also frequently used in chemically highly resistant borosilicate glasses and, moreover, as a heavy element, also acts as a radiation blocker. Surprisingly, however, it has been shown that a high BaO content is not necessary in the disc-shaped glass articles according to embodiments of the present disclosure to ensure advantageous radiation shielding properties. Even small amounts of less than 2 wt.% BaO, for example less than 1.5 wt.% BaO and particularly preferably less than 1 wt.% BaO, are therefore preferred, and it may also be provided that the glass or...The disc-shaped glass article can be free of BaO except for unavoidable traces, which generally do not exceed 500 ppm per component by weight. This is advantageous because BaO is a heavy component and thus increases the payload, and the density of the glass in the disc-shaped article should ideally not be too high. Furthermore, a commonly used raw material for BaO, namely BaCOs, is classified as a hazardous substance, so for this reason as well, the BaO content in the glass should be kept as low as possible. SCHOTT AG 16 03.03.2026 P06334 WO.

[0083] According to one embodiment of the disc-shaped glass article, the glass has a density between 2.4 g / cm³. 3 and 2.7 g / cm³ 3 preferably between 2.45 g / cm³ 3 and 2.65 g / cm² 3, on. Such a design, which is particularly advantageous with regard to extraterrestrial applications because of the payload to be considered here, can advantageously be combined with a low BaO content in the glass.

[0084] According to one embodiment of the disc-shaped glass article, the glass comprises less than 3 wt.% IJ₂O, preferably less than 2 wt.% IJ₂O, and particularly preferably less than 1 wt.% IJ₂O. IJ₂O is a component that can lower the melting point in the glasses according to embodiments, but can be disadvantageous due to high raw material costs and generally due to the tendency to segregate and crystallize in glasses.

[0085] It is therefore preferable if the glass is free of IJ2O except for unavoidable traces.

[0086] According to a further embodiment of the disc-shaped glass article, the glass comprises less than 10 wt.% Na₂<3 and / or less than 4 wt.% CaO and / or less than 3 wt.% MgO. These components are an alkali or two alkaline earth oxides, which can be advantageous in the glass of the disc-shaped article according to these embodiments, as they improve the meltability of the glass. They also serve to achieve a suitable, adapted coefficient of thermal expansion. However, these components should not be present in excessively high concentrations in the glass of the disc-shaped article, since they can reduce the chemical resistance of the glass and, in excessive concentrations, would lead to excessive thermal expansion.

[0087] According to one embodiment, the disc-shaped glass article has a surface roughness, specified as R a, of 1 nm, preferably less than 0.5 nm or less. Preferably, the surface of the disc-shaped glass article is fire-polished, thus representing a native surface. Such low roughness R a These are characteristic of fire-polished, free-form thin glass, while mechanically polished glass can exhibit significantly higher roughness values. Low roughness of the disc-shaped glass article is advantageous for the formation of a well-adhering, non-delaminating bond with the other components. SCHOTT AG 17 03.03.2026 P06334 WO

[0088] Components of the solar module for which the disc-shaped glass article is intended to serve as a cover. Such surfaces of the disc-shaped glass article, with their very low roughness as specified above, are also very well suited for coatings that may be applied to the disc-shaped glass article, for example, anti-reflective coatings. For instance, such a low roughness of the disc-shaped glass article can be advantageously achieved in a drawing process, in particular a so-called down-draw process, such as an overflow fusion process or a down-draw process through a slot.

[0089] In particular, the present disclosure also relates to a glass article, manufactured or manufacturable by a process according to an embodiment.

[0090] According to a further embodiment of the disc-shaped glass article, the glass has a refractive index na of at least 1.51 and at most 1.53 at a wavelength of 588 nm. A refractive index in this range is advantageous for avoiding reflection losses at interfaces with other materials, for example, in a solar module.

[0091] According to another embodiment of the glass article, the electrical resistance of the glass is between more than 10 13 Q-cm and less than 10 15 Q-cm at a temperature of 20 °C.

[0092] The disc-shaped glass articles according to the disclosure are generally suitable as cover glasses or cover plates or front substrates for solar panels for space applications, such as for satellites or spacecraft or space stations.

[0093] The present disclosure thus also relates generally to a front-end unit for a solar module, in particular for mobile applications such as mobile devices, means of transport, and / or manned and / or unmanned aircraft, especially for space applications, comprising a disc-shaped glass article according to an embodiment of the present disclosure and an adhesive layer, which is preferably applied over the entire surface of one side of the disc-shaped glass article, wherein the adhesive layer particularly preferably comprises at least one of the following materials: SCHOTT AG 18 03.03.2026 P06334 WO

[0094] Butyl polymer, EVA, PVB, SMP, or a preferably transparent silicone. EVA generally refers to ethylene vinyl acetate. PVB denotes the polymer polyvinyl butyral. SMP is an abbreviation for a silane-modified polymer.

[0095] Furthermore, the present disclosure also relates generally to a solar module, in particular for mobile applications such as mobile devices, means of transport, transport equipment and / or manned and / or unmanned aircraft, in particular for space applications, comprising a disc-shaped glass article of an embodiment, preferably a back element which is in particular designed as a module frame, a solar cell which is preferably arranged between the back element and the disc-shaped glass article, and an adhesive layer which connects the disc-shaped glass article and the solar cell together, wherein the adhesive layer particularly preferably comprises at least one of the following materials: a butyl polymer, EVA, PVB, SMP or a preferably transparent silicone.

[0096] The solar cell can be designed in particular as a single-junction, where silicon cells are used in particular, or as a multi-junction, especially using gallium arsenide cells; however, gallium indium phosphide cells or thin-film cells can also be made of or comprise amorphous silicon (a-Si) or of or comprise materials with a so-called perovskite structure, cadmium telluride or copper indium gallium selenide (GIGS).

[0097] The present disclosure also relates to a use. In particular, the present disclosure relates to the use of a disc-shaped glass article according to embodiments of the disclosure and / or a front face unit according to an embodiment for a solar module, especially for mobile applications, for example mobile devices, means of transport, and / or manned and / or unmanned aircraft, especially for space applications.

[0098] Furthermore, the present disclosure also relates to the use of a solar module according to the present disclosure for mobile applications, for example mobile devices, SCHOTT AG 19 03.03.2026 P06334 WO

[0099] Means of transport, means of transport and / or manned and / or unmanned flying objects, especially for space applications.

[0100] Examples

[0101] The invention is explained in more detail below using examples. Table 1 below shows the composition of five example glasses that meet the specifications of the present disclosure. The values ​​in the table are given in wt.%. Totals deviating from 100 wt.% are due to rounding.

[0102] Table 1:

[0103] Example. Example. Example. Example. Comparison. Comparison. 1 2 3 4 5 Example 1 Example 2 Glass composition

[0104] SiO2Gew.-% 63,4 61,4 65,0 64,16 63,23 59,79 60,1 AI2O3 Gew.-% 4,9 4,7 5,0 4,9 4,9 9,4 9,4 B2O3 Gew.-% 8,2 7,8 7,7 7,8 8,0 6,3 6,0 Li2O Gew.-% 0,2 0,2 0,22 0,22 0,23

[0105] Na2O Gew.-% 5,8 5,6 5,7 5,6 6,0 6,4 6,4 K2O Gew.-% 5,1 4,9 4,9 4,8 5,4 4,6 10,9 MgO Gew.-% 1,9 1,8 1,9 1,8 1,9 1,8

[0106] CaO Gew.-% 1,9 0,3 SrO Gew.-% 3,7 3,6 3,6 3,6 3,7

[0107] BaO Gew.-% 0,05 0,04

[0108] ZnO Gew.-% 3,9 3,2 3,8 3,7 3,8 4,5 5,9 TiO2Gew.-% 0,10 0,09 0,11 0,10 0,10 0,1 Bi2O3 Gew.-% 0,00 3,44 0,0 0,0 0,0

[0109] CeO2Gew.-% 2,6 2,5 2,0 3,1 2,6 4,9 0,8 Fe2O3 Gew.-% 0,01 0,01

[0110] SO3Gew.-% 0,04 0,04 0,01 0,04

[0111] CI Gew.-% 0,1 0,1 0,1 0,1 0,1 0,1 0,1 3-CeO2 + AI2O3 Gew.-% 12,3 12,6 11,0 14,2 12,7 24,5 11,8 Glaseigenschaften

[0112] CTE (2O;3OO °C) [ppm / K] 6,81 6,84 6,72 6,77 6,93 7,02 8,5 Tg [°C] 560 549 561 562 560 580 565

[0113]

[0114] Density [g / cm³] 3 ] 2.54 2.61 2.53 2.55 2.55 2.55 2.50SCHOTT AG 20 March 3, 2026 P06334 WO

[0115] - - - nd — 1.516 1.523 1.520 1.520

[0116] — - - - - Vd 60.1 57.9 58.2 Sample thickness [pm] 120 111 - - - 117 - Spectral transmission for a thickness L25 pm

[0117] at 300 nm [%] 0.8 0.1 - - - 0.1 14.2 at 310 nm [%] 0.9 0.2 - - - 0.1 13.4 at 320 nm [%] 1.8 0.7 - - - 0.1 17.5 at 330 nm [%] 10.0 6.8 - - - 0.2 34.5 at 400 nm [%] 90.1 88.7 - - - 77.8 91.0 at 450 nm [%] 91.1 90.5 - - - 86.5 91.3 500 - 1800 nm [%] 92.3 92.0 - - - 91.9 -

[0118]

[0119] (average)

[0120] Solarization, transmission decrease for a thickness of 125 µm

[0121] after 15 hours

[0122] 400 - 450 nm [%] 0.5% 0.6% - - - 0.3% 0.18% (average)

[0123] 450 - 1800 nm [%] 0.1% 0.0% - - - 0.1% (average) 0.04% after 100 h

[0124] 400 - 450 nm [%] 0.9% - - - 0.3% 0.19% (average)

[0125] 450 - 1800 nm [%] 0.2% - - - 0.1% 0.04% (average)

[0126] Deglazing tendency

[0127] UEL [°C] 1060 1045 - - - >1250 log (r|0EG / dPa s) 4.3 4.2 - - - 3.2

[0128]

[0129] For the advantageous disc-shaped glass articles, whose spectra are shown in Fig. 2 with reference numerals 2 and 7, as well as for glass articles with spectra 1 and 5, further solarization tests were carried out using a Philips HOK 4 type UV lamp. The results of these solarization tests show that the mean spectral transmission in the wavelength range from 450 nm to 1800 nm changes after irradiation for 100 hours with UV-A light at 210 W / m². 2 UV-B light with 170 W / m² 2 as well as UV-C light with 250 W / m² 2changes by less than 1%. The transmission values ​​given here in the context of the solarization experiments over the two wavelength ranges 400–450 nm and SCHOTT AG 21 03.03.2026 P06334 WO

[0130] 450 - 1800 nm is the arithmetic mean of the spectral transmission over the specified wavelength range.

[0131] Description of the drawings

[0132] The invention will be further explained below with reference to the drawings. The drawings show:

[0133] Fig. 1 shows the influence of the redox ratio of cerium (the ratio of Ce 3+ to Ce 4+ ) on the position of the UV edge,

[0134] Figs. 2 and 3 Transmission spectra of different disc-shaped glass articles

[0135] Fig. 4 is a schematic and not to scale representation of a disc-shaped glass article according to embodiments of the disclosure,

[0136] Fig. 5 is a schematic and not to scale representation of a front-end unit comprising a disc-shaped glass article according to embodiments, as well as

[0137] Fig. 6 is a schematic and not to scale representation of a solar module according to one embodiment.

[0138] Fig. 1 shows, by way of example and without limitation to a specific embodiment, the influence of the redox ratio of cerium, i.e., within the scope of the present disclosure, the ratio of the two oxidation states Ce. 4+ and Ce 3+ relative to each other, to the position of the UV edge and its steepness in a disc-shaped glass article according to one embodiment.

[0139] Reference numeral 8 in Fig. 1 shows the transmission curve of a disc-shaped glass article with a thickness of 125 mm, whereby this glass article is not a glass article according to any embodiment. In contrast, reference numeral 9 denotes the transmission curve of a disc-shaped glass article which, with respect to the transmission profile at the UV edge, SCHOTT AG 22 03.03.2026 P06334 WO

[0140] within the specifications of disc-shaped glass articles according to the present disclosure,

[0141] - with a spectral transmittance of less than 3% at a wavelength of 320 nm and with a spectral transmittance of at least 87% at a wavelength of 400 nm

[0142] - and furthermore, in the wavelength range from 500 nm to 1800 nm, the mean spectral transmission, determined as the arithmetic mean of the measured spectral transmittances in this wavelength range, is at least 92%, and optionally one of the following additional characteristics:

[0143] - at a wavelength of 450 nm, a spectral transmittance of at least 88%, preferably at least 89%, particularly preferably at least 90%.

[0144] Surprisingly, the compositions of these two disc-shaped glasses hardly differ from each other – however, the glass of the disc-shaped glass article, whose transmission spectrum is designated with the reference numeral 8, was melted under oxidizing conditions. This can be achieved, for example, by adding antimony oxide and nitrate as oxidizing agents to the molten glass. This results in cerium being present predominantly in the tetravalent positive oxidation state, i.e., as Ce. 4+ This results in a more pronounced steepness of the UV edge and higher overall spectral transmittance values. Therefore, it can be very advantageous to melt the glass panes according to certain embodiments under oxidizing conditions.

[0145] The inventors generally assume, without limiting themselves to the specific example mentioned above, that the proportion of Ce 4+, in relation to the sum of the redox states Ce that are relevant here 3+ and Ce 4+ , with appropriate melting conditions, at least 30%, preferably at least 50%, and particularly preferably at least 70%. Similarly, this means that the proportion of Ce 3+ , in relation to the sum of the redox states Ce that are relevant here 3+ and Ce 4+ at most 70%, preferably at most 50%, and most preferably at most 30%. The low proportion of Ce is particularly relevant from a technical standpoint. 3+ -Content based on the total content, which for the glasses considered here is the sum of the Ce content 3 and Ce 4+ is in the glass. Because this widens the transmission edge. SCHOTT AG 23 03.03.2026 P06334 WO

[0146] or flattens the transmission curve. A high proportion of Ce 4+, which results in particular from an oxidizing melt flow, is therefore especially advantageous for the application considered here.

[0147] In general, without limiting oneself to the specific example shown in Fig. 1, the disc-shaped glass article according to one embodiment is therefore designed such that it comprises a glass, wherein the relative proportion of the Ce 3+ of the total cerium in the glass, determined as the sum of Ce 3+ and Ce 4+ , at most 70%, preferably at most 50% and most preferably at most 30%.

[0148] In general, without limiting oneself to the specific example shown in Fig. 1, the disc-shaped glass article according to one embodiment is therefore designed such that it comprises a glass, wherein the ratio of Ce 3+ to Ce 4+ in the glass 3+ / Ce 4+ , less than 2, preferably less than 1 and especially preferably less than 0.5.

[0149] Figure 2 shows two exemplary transmission spectra of two disc-shaped glass articles according to the invention with a thickness of 125 µm. The transmission spectrum with reference numeral 1 corresponds to embodiment 2 according to Table 1, and the transmission spectrum with reference numeral 2 corresponds to embodiment 1 according to Table 1.

[0150] Both transmission spectra exhibit exceptionally high spectral transmission in the visible spectral range, which is essentially determined by reflection losses at the two surfaces. Transmission spectra 1 and 2 were obtained for disc-shaped glass articles, which were uncoated. It should be noted that both disc-shaped glass articles have no coating whatsoever, in particular no antireflective coating such as is frequently used on solar cover glass. With such antireflective coatings, the spectral transmission could be increased even further to over 95% and higher. For the purposes of this disclosure, antireflective coatings are generally understood to be optically effective coatings, which can be formed as single layers, then with a low refractive index of less than 1.4, or as optical interlayer systems comprising at least one high-refractive-index and

[0151] At least one low-refractive-index layer is required. Such interlayer systems often consist of alternating layers of Si2 as the low-refractive-index layer and Ti2 as the high-refractive-index layer, although other configurations are possible and known. In any case, a coating, whether a single layer or an interlayer system, represents an additional cost factor. For solar cells, a relatively simple antireflective coating, e.g., made of MgF2, is frequently used, which is significantly less expensive than the multilayer systems described above. Furthermore, such antireflective coatings are also susceptible to damage. Therefore, it is advantageous that such coatings are not required for glass articles according to the present disclosure.

[0152] Nevertheless, the disc-shaped glass articles according to the invention can readily be used in combination with antireflective coatings, such as the MgF2 system. In the near-UV range, the spectral transmission drops very sharply to values ​​below 1% despite the small glass thickness. This protects an adhesive or polymer, which is typically arranged between the cover glass and the solar cell, from excessive UV radiation that could damage the adhesive or polymer.

[0153] Figure 3 shows five transmission spectra 1, 2, 3, 4, and 5 of disc-shaped glass articles with a thickness of 125 µm. Only the wavelength range from 250 nm to 450 nm is shown, which, due to its gradient shape, is sometimes referred to simply as the blue edge or UV edge to make the difference between the spectra clearer than in Figure 2. Transmission spectrum 1, as in Figure 2, corresponds to Example 2 according to Table 1, and transmission spectrum 2 corresponds to embodiment 1 according to Table 1. Transmission spectrum 3 corresponds to a commercially available disc-shaped glass article of the applicant with the glass designation "0787". Finally, transmission spectrum 4 corresponds to comparative example 1, and transmission spectrum 5 corresponds to another comparative example from DE 1020232118 163 of the applicant.

[0154] It is clearly evident that the transmission spectrum 3 extends deep into the UV down to a wavelength of 250 nm, which does not correspond to the disc-shaped glass articles according to the invention.

[0155] The transmission spectra 1 and 2 according to the invention exhibit at 400 nm, i.e. the beginning of the SCHOTT AG 25 03.03.2026 P06334 WO

[0156] In the visible spectral range, the glasses already exhibit a spectral transmission of more than 87%, with the spectral transmission dropping off very rapidly in the UV range. Thus, the glasses according to the invention typically exhibit a spectral transmission of < 10% at 330 nm and a spectral transmission of less than 3% at a wavelength of 320 nm. Overall, spectra 1 and 2 therefore show a significantly steeper UV edge than transmission spectrum 3.

[0157] Transmission spectra 4 and 5 also exhibit very steep UV edges, with the spectra in the figure shifted by approximately 10 nm towards longer wavelengths. However, these corresponding glasses exhibit a relatively strong tendency to devitrify, i.e., a relatively high upper devitrification temperature (OEG) of at least 1210°C, corresponding to a viscosity r| or a log (r|oEG / dPa-s) of 3.5. These glasses are unsuitable for hot forming using a conventional thin-glass drawing process and therefore do not meet the requirements of the present invention.

[0158] Fig. 4 shows a general schematic representation, not to scale, of a disc-shaped glass article 10 according to various embodiments. The disc-shaped glass article is generally designed such that it has two sides 11, 12, which are preferably parallel to each other. Parallel alignment of the two sides 11, 12 means that the angle between the normal vectors to the sides 11, 12 is no more than 5°. The lateral dimension of the glass article 10 in one spatial direction of a Cartesian coordinate system is at least one order of magnitude smaller than the two other lateral dimensions along the two other spatial directions perpendicular to this first spatial direction. This first lateral dimension is also referred to as the thickness d of the glass article, and the two other lateral dimensions as length and width.In other words, the thickness d of the glass article 10 is at least one order of magnitude smaller than the length and width of the glass article 10.

[0159] In the context of this disclosure, a disk or disk-shaped formation is generally understood to mean that the surfaces 11, 12 can have any shape, but are preferably rectangular. In the field of cover glasses for solar cells, wafer-like formats are also common, e.g., a square or SCHOTT AG 26 03.03.2026 P06334 WO

[0160] A rectangular shape with truncated corners, resulting in an octagonal shape. Other configurations are possible, though not preferred. Sides 11 and 12 can also be understood as the side faces or surfaces of the glass article 10, in contrast to the circumferential edge surface 13.

[0161] Fig. 5 is a schematic and not-to-scale representation of a sectional view through a front panel unit 100 for a solar module (not shown). The front panel unit is particularly suitable for mobile applications such as mobile devices, means of transport, and / or manned and / or unmanned aerial vehicles, especially for space applications. The front panel unit 100 generally comprises a disc-shaped glass article 10 according to one embodiment of the disclosure and an adhesive layer 21. This is preferably applied over the entire surface of one side 11, 12 (not specified here) of the disc-shaped glass article 10. The adhesive layer 21 particularly preferably comprises at least one of the following materials: a butyl polymer, EVA, PVB, SMP, or a preferably transparent silicone.

[0162] Finally, Fig. 6 shows a schematic and not-to-scale representation of a sectional view of a solar module according to the disclosure. The solar module 20 is also particularly suitable for mobile applications, such as mobile devices, means of transport, and / or manned and / or unmanned aerial vehicles. The solar module 20 is especially suitable for space applications. It comprises a disc-shaped glass article 10 according to embodiments of the present disclosure. In general, without limiting itself to the schematic example shown in Fig. 6, the solar module 20 can comprise a rear element 300. This can, for example, be designed as a module frame. The solar module 20 further comprises a solar cell 200. This is preferably arranged between the rear element 300, if present, and the disc-shaped glass article 10.In general, the solar module 20 comprises the adhesive layer 21, which connects the disc-shaped glass article 10 according to embodiments and the solar cell 200. The adhesive layer 21 particularly preferably comprises at least one of the following materials: a butyl polymer, EVA, PVB, SMP, or a preferably transparent silicone. SCHOTT AG 27 03.03.2026 P06334 WO.

[0163] List of reference signs

[0164] 1, 2, 3, 4, 5, 8, 9 Transmission spectra of disc-shaped glass articles before solarization

[0165] 10 disc-shaped glass items

[0166] 11, 12 pages of the glass article

[0167] 13 Circumferential edge surface of the glass article 100 Front side unit

[0168] 20 solar modules

[0169] 21 adhesive layer

[0170] 200 solar cells

[0171] 300 back panel elements

[0172] d thickness of the glass article

[0173]

Claims

SCHOTT AG 28 03.03.2026 P06334 WO Patent claims 1. Disc-shaped glass article (10) which, with a thickness (d) of the disc-shaped glass article (10) of 125 pm, has a spectral transmission of less than 3% at a wavelength of 320 nm and a spectral transmission of at least 87% at a wavelength of 400 nm. - wherein the disc-shaped glass article (10) comprises a cerium oxide-containing glass whose upper devitrification temperature OEG is < 1240°C and preferably <1210°C, and / or - for its viscosity at the upper devitrification temperature T|OEG log (noEG / dPa-s) > 3.3, preferably > 3.5 and more preferably > 4.0 and optionally one of the further features, each based on a thickness (d) of the disc-shaped glass article (10) of 125 pm: - In the wavelength range from 500 nm to 1800 nm, the average transmission, determined as the arithmetic mean of the measured spectral transmission in this wavelength range, is at least 91%, preferably at least 92%. - at a wavelength of 450 nm, the spectral transmission is at least 88%, preferably at least 89%, and particularly preferably at least 90%.

2. Disc-shaped glass article (10) according to claim 1, having a thickness between at least 30 pm and at most 175 pm, preferably between at least 100 pm and at most 150 pm.

3. Disc-shaped glass article (10) according to any one of claims 1 to 3, wherein the disc-shaped glass article (10) comprises a glass comprising SiO2, B2O3 and CeO2, and wherein these components are preferably included in the following regions, expressed as wt.% on an oxide basis, of the glass: SiÜ2 at most 70, preferably at most 67, particularly preferably at most 65 and preferably at least 55, preferably at least 57, particularly preferably at least 59. SCHOTT AG 29 03.03.2026 P06334 WO B2O3 greater than 0, preferably at least 4.5 and particularly preferably at least 5 and preferably at most 15, preferably at most 10.0, and particularly preferably at most 9.

4. Disc-shaped glass article (10) according to any one of claims 1 to 3, wherein the glass preferably comprises these components in the following areas, specified as wt.% on an oxide basis: CeO2 at least 1.0, preferably at least 1.5, particularly preferably at least 2 and preferably at most 4.5, preferably at most 3.5, particularly preferably at most 3.

0. AI2O3 0, preferably at least 2 and particularly preferably at least 3 and preferably at most 14, preferably at most 10, particularly preferably at most 6, where the following also applies preferably to the contents in wt.%: 3'CeO2 + Al2O3 < 17 wt.%, preferably < 15 wt.%, more preferably < 13 wt.%.

5. Disc-shaped glass article (10) according to any one of claims 1 to 4, wherein the glass has a coefficient of thermal expansion (GTE) in the temperature range of 20 °C to 300 °C, CTE(20;300°C), of less than 7.5-10 6 / K, preferably less than 7.4 10 6 / K, exhibits, particularly preferably of less than 7.2 ■ 10 6 / K, especially preferred by less than 7.1 -10- 6 / K, especially preferred by those with less than 7.0 10 6 / K and preferably of at least 6.5-10- 6 / K exhibits.

6. Disc-shaped glass article (10) according to any one of claims 1 to 5, wherein the glass comprises TiO2, wherein preferably the glass comprises at most 4.5 wt.% TiO2, more preferably at most 1.0 wt.% TiO2, more preferably at most 0.2 wt.% TiO2.

7. Disc-shaped glass article (10) according to any one of claims 1 to 6, wherein the glass comprises less than 10 wt.% BaO, preferably less than 1.0 wt.% BaO, particularly preferably less than 0.1 wt.% BaO. SCHOTT AG 30 03.03.2026 P06334 WO 8. Disc-shaped glass article (10) according to any one of claims 1 to 7, having a surface roughness specified as R a , of < 1 nm, preferably < 0.5 nm.

9. Disc-shaped glass article (10) according to any one of claims 1 to 8, wherein the glass has a refractive index na of at least 1.51 and at most 1.

53.

10. Disc-shaped glass article (10) according to any one of claims 1 to 9, wherein the glass has a density between 2.4 g / cm³ 3 and 2.7 g / cm³ 3 exhibits, preferably between 2.45 g / cm³ 3 and 2.65 g / cm² 3 .

11. Disc-shaped glass article (10) according to any one of claims 1 to 10, wherein the glass comprises less than 3 wt.% IJ2O, preferably less than 2 wt.% IJ2O and particularly preferably less than 1 wt.% IJ2O.

12. Disc-shaped glass article (10) according to any one of claims 1 to 11, wherein the glass comprises less than 10 wt.% Na2Ü and / or less than 4.0 wt.% CaO and / or less than 3.0 wt.% MgO.

13. Disc-shaped glass article (10) according to one of claims 1 to 12, wherein the mean spectral transmission in the wavelength range from 450 nm to 1800 nm is increased by irradiation for 100 h with UV-A light at 210 W / m² 2 , with UV-B light at 170 W / m² 2 as well as UV-C light with 250 W / m² 2 changes by less than 1%, preferably less than 0.5%.

14. Disc-shaped glass article (10) according to any one of claims 1 to 13, comprising a glass, wherein the relative proportion of the Ce 3+of the total cerium in the glass, determined as the sum of Ce 3+ and Ce 4+ , at most 70%, preferably at most 50% and particularly preferably at most 30%. SCHOTT AG 31 03.03.2026 P06334 WO 15. Disc-shaped glass article (10) according to any one of claims 1 to 14, comprising a glass, wherein the ratio of Ce 3+ to Ce 4+ in the glass 3+ / Ce 4+ , less than 2, preferably less than 1 and especially preferably less than 0.

5.

16. Front panel unit (100) for a solar module (20), in particular for mobile applications such as mobile devices, means of transport, transport equipment and / or manned and / or unmanned aircraft, in particular for space applications, comprising a disc-shaped glass article (10) according to one of claims 1 to 15 and an adhesive layer (21) which is preferably applied over the entire surface of one side (11, 12) of the disc-shaped glass article (10), wherein the adhesive layer (21) particularly preferably comprises at least one of the following materials: a butyl polymer, EVA, PVB, SMP or a preferably transparent silicone.

17. Solar module (20), particularly for mobile applications such as mobile devices, means of transport, transport equipment and / or manned and / or unmanned aircraft, particularly for space applications, comprising a disc-shaped glass article (10) according to any one of claims 1 to 15, preferably a back element (300), which is particularly designed as a module frame, a solar cell (200), which is preferably arranged between the back element (300) and the disc-shaped glass article (10), and an adhesive layer (21) which connects the disc-shaped glass article (10) and the solar cell (200), wherein the adhesive layer (21) particularly preferably comprises at least one of the following materials: a butyl polymer, EVA, PVB, SMP or a preferably transparent silicone.

18. Use of a disc-shaped glass article (10) according to any one of claims 1 to 15 and / or a front-end unit (100) according to claim 16 for a solar module (20), in particular for mobile applications, for example mobile devices, means of transport, transport equipment and / or manned and / or unmanned aerial vehicles, in particular for space applications. SCHOTT AG 32 03.03.2026 P06334 WO 19. Use of a solar module (20) according to claim 17 for mobile applications, for example mobile devices, means of transport, means of transport and / or manned and / or unmanned flying objects, in particular for space applications.

20. Method for producing a disc-shaped glass article (10), in particular a disc-shaped glass article (10) according to any one of claims 1 to 15, in a drawing process, in particular a so-called down-draw process, for example an overflow fusion process or a down-draw process through a slot.

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