Device for generating low-temperature plasma

Abstract

The invention relates to a device for generating low-pressure plasma, comprising a glass-comprising, preferably disk-shaped, dielectric having a low thickness, a low warpage, a low roughness and low total thickness variation.

Description

[0001] August 4, 2025

[0002] Device for generating low-temperature plasma

[0003] Description

[0004] Field of invention

[0005] The present application relates to a device for generating low-temperature plasma with a glass-encompassing dielectric, as well as the dielectric and its use.

[0006] Background of the invention

[0007] In devices for generating low-temperature plasma, the plasma generated in them is used, for example, for air or exhaust gas purification, e.g. for CO2 decomposition, thereby replacing a thermal reaction that would otherwise be necessary.

[0008] A key aspect of such devices for generating low-temperature plasma is the production of a plasma that is as homogeneous as possible. The plasma is generated between electrodes in the discharge chamber. The electrodes are covered with dielectric barriers.

[0009] These dielectric barriers can be made of materials such as ceramic, aluminum oxide or glass, for example borosilicate glass.

[0010] Devices for generating low-temperature plasma with dielectric barriers made of borosilicate glass have already been described in patent literature, for example in AU 2005201370 Al, CN 216930385 U, US 2005023128 A, US 2019011400 A, WO 14078821 Al, WO 23019081 A, WO 23019082 A, WO 23019083 A.

[0011] The aforementioned requirements for plasma homogeneity are not yet sufficiently met by existing devices and components for generating low-temperature plasma. Further improvements are needed. 04 / 08 / 2025

[0012] Object of the invention

[0013] One object of the invention is therefore to provide a device for generating low-temperature plasma that fulfills the described requirements profile for a device for generating low-temperature plasma. A further aspect is the use of a dielectric for such a device for generating low-temperature plasma. Another aspect is the provision of such a dielectric.

[0014] Summary of the invention

[0015] The object of the invention is achieved by the subject matter of the independent claims. Preferred and specific embodiments are found in the dependent claims and the description of the present disclosure.

[0016] It has been shown that a crucial aspect for generating a highly homogeneous plasma is the arrangement of the electrodes in the discharge chamber. They should be positioned at a conformal distance from one another. The stringent requirements for the arrangement and / or uniformity of the electrode bodies, or for the dielectric barriers covering the electrodes, are evident from the small dimensions of the gap between them. The width of the plasma gap, i.e., the distance between the dielectric barriers, is typically only between 0.3 mm and 5 mm, usually between 1 mm and 5 mm. The distance between the electrodes, the electrode gap, is determined by the width of the plasma gap and the thickness of the dielectrics covering the spaced-apart electrodes. The terms dielectric and dielectric barrier are used synonymously in this disclosure.

[0017] The present invention relates to a device for generating low-temperature plasma comprising a first dielectric comprising a glass-enclosing, preferably glass-based, first electrode at least partially covered with the first dielectric, a plasma source, a discharge chamber, an electrical energy source, a second dielectric, and a second electrode at least partially covered with the second dielectric, wherein the electrodes are arranged such that a predetermined gap, the plasma gap, separates the first and the second dielectric, wherein the glass-enclosing dielectric has a thickness of max. 1.5 mm and, at a thickness of 1 mm over an area of ​​1150 mm x 850 mm, has a warp of at most 300 pm, a thickness variation (TTV) of at most 40 pm, and a roughness Ra of less than 5 nm, preferably less than 3 nm.

[0018] The device for generating low-temperature plasma makes it possible to generate a plasma at comparatively low temperatures.

[0019] The electrodes are placed in a discharge chamber and serve to generate an electric field. They are made of a material with good electrical conductivity, preferably stainless steel, aluminum, or copper. The discharge chamber is the area in which the plasma is generated.

[0020] The electrodes, which are at least partially covered with the respective dielectric, are preferably completely covered with the dielectric at least on the side that borders the gap between the electrodes with the side of the other electrode. Preferably, all sides are completely covered with the respective dielectric.

[0021] The preferably plate-shaped electrodes are arranged equidistant from each other. The gap between them, the electrode gap, preferably has a width between 1.7 mm and 8 mm. 04.08.2025

[0022] The dielectrics covering opposing electrodes are arranged equidistantly from each other. The gap between them, the plasma gap, preferably has a width of 3 mm ± 2 mm or between 0.3 mm and 5 mm.

[0023] The plasma source generates the low-temperature plasma. Various technologies exist for plasma generation, including direct and indirect plasma sources. In direct plasma generation, the plasma is generated directly within the gas discharge chamber by applying a high voltage between the electrodes, creating an electric field between the two opposing dielectric barriers. In indirect plasma generation, the plasma is generated outside the reaction chamber and then introduced into the reactor. An example of this is the plasma jet. Here, the plasma is generated in a separate chamber and transported into the reaction chamber by a gas stream.

[0024] To use the device, a suitable fluid, preferably a gas such as argon, silane, methane, air, or flue gases, is introduced into the plasma source. The pressure is set to atmospheric pressure to enable plasma generation at low temperatures. For this purpose, the device may include gas supply and discharge mechanisms and pressure control devices.

[0025] The device can include measuring and control instruments that enable the control and optimization of the plasma. These instruments contain sensors that can monitor parameters such as gas pressure, voltage, and current.

[0026] The device may include cooling and insulating means, because since the low-temperature plasma operates at comparatively low temperatures, efficient cooling is required to avoid overheating.

[0027] Insulating materials can protect the surroundings from the heat of the plasma source.

[0028] Depending on the application, specialized devices can be connected to the plasma source. Examples include surface treatment systems, sterilization equipment, or medical instruments. Possible applications include, for example, exhaust gas purification or carbon dioxide decomposition.

[0029] The second dielectric can also comprise glass or consist of glass.

[0030] Preferably, like the first dielectric, it comprises glass. Preferably, like the first dielectric, it consists of glass. Preferably, the first and second dielectrics consist of the same glass. The embodiments described below for the first dielectric also represent preferred embodiments for the second dielectric.

[0031] To simplify manufacturing and logistics in the production of the device, but above all to optimize the gap shape between the electrodes, it is preferable to use the same embodiments in the device for both dielectrics.

[0032] The device for generating low-temperature plasma can also comprise more than two electrodes, which are at least partially covered with a dielectric. In this case, the additional electrodes preferably also have dielectrics corresponding to the embodiments described for the dielectrics of the first and second electrodes.

[0033] The first dielectric has a thickness of at most 1.5 mm, preferably at least 0.5 mm and at most 1.2 mm, preferably less than 1 mm, and particularly preferably at most 0.7 mm. It is preferably disk-shaped. It is preferably neither thermally nor chemically prestressed.

[0034] Preferred formats of this dielectric are, preferably depending on the electrode format, lengths of at least 90 mm, more preferably at least 150 mm, particularly preferably at least 300 mm, and widths of at least 60 mm, more preferably at least 100 mm, where width denotes the shorter distance and length the longer distance, for example formats of 60 mm x 90 mm or 120 mm x 150 mm or 200 mm x 300 mm or 300 mm x 300 mm or 500 mm x 500 mm or 100 mm x 500 mm or 100 mm x 400 mm or 100 mm x 390 mm or 100 mm x 300 mm. 04.08.2025

[0035] It has been shown that a high degree of dimensional stability of the dielectric according to the invention is important for the trouble-free and effective operation of the device according to the invention. Criteria for the dimensional stability of, for example, a disc-shaped article are its warping and the variation in its thickness.

[0036] The warping of the preferably disk-shaped first dielectric is relevant for maintaining a constant distance between the electrodes. This warping is also referred to as the arc. It should be as small as possible and, according to the invention, is at most 300 pm over an area of ​​1150 mm x 850 mm with a dielectric thickness of 1 mm. With a greater warping, undesirable localized ignition occurs at the points of smallest electrode spacing during operation of the device according to the invention. Preferably, the warping is a maximum of 200 pm for the aforementioned format, and more preferably a maximum of 100 pm. This enables particularly homogeneous, planar plasma ignition during operation of the device.

[0037] Preferably, the warping is at most 250 pm, preferably at most 200 pm, for a thickness of 0.9 mm on an area of ​​390 mm x 560 mm.

[0038] Preferably, the warping is at most 100 pm for a thickness of 1.1 mm over an area of ​​460 mm x 430 mm.

[0039] Preferably, the warping is at most 100 pm for a thickness of 0.7 mm over an area of ​​460 mm x 430 mm.

[0040] The warp is determined on a warp measuring table. Optical sensors scan the disk. By traversing the surface in a linear fashion, the sensors detect the height differences on the disk's surface. This data is collected in real time and sent to an evaluation system. The collected data is analyzed by software that calculates the disk's deformation. This is done by comparing the measured height differences with an ideal, undeformed surface. The results are displayed as graphs or numerical values ​​indicating the disk's warping. 04 / 08 / 2025

[0041] When describing warp, a distinction is made between individual warp and total warp. Individual warp represents the change in the flatness of a single measurement track. No results for individual warp are given in the present patent application. Only results for total warp are given in the present patent application. Total warp is calculated from the minimum distance between all measurement tracks and the maximum distance between all measurement tracks.

[0042] In a preferred embodiment, the dielectrics of the opposing electrodes are aligned in such a way that their two curvatures cancel each other out, i.e., they are arranged in a dished shape.

[0043] The variation in thickness across the width and length of the preferably disk-shaped first dielectric is relevant for setting a gap with a constant distance between the electrodes. This variation in thickness is also referred to as total thickness variation (TTV). It should be as small as possible and, according to the invention, is at most 40 pm over an area of ​​1150 mm x 850 mm. With a larger thickness variation, undesirable localized ignition occurs at the points of smallest electrode spacing during operation of the device according to the invention. Preferably, the thickness variation over the aforementioned area is less than 40 pm. A thickness variation of at most 30 pm, less than 30 pm, or less than 20 pm is preferred, particularly preferably at most 15 pm or at most 10 pm, and most preferably at most 5 pm or at most 2 pm over the aforementioned area.This enables particularly homogeneous, planar plasma ignition during operation of the device.

[0044] It is preferred that the aforementioned TTV upper limits not only apply to formats up to 977500 mm 2 , but for formats up to 3,910 x 100 mm 2 , for example, 2300 mm x 1700 mm.

[0045] Unlike warping, thickness variation is practically independent of thickness. 04 / 08 / 2025

[0046] The thickness variation is set during hot forming on the glass ribbon and determined using the double reflection method.

[0047] Another important characteristic for creating a uniform distance between opposing dielectrics is the roughness Ra of the dielectric. It is, for example, less than 5 nm when measured with an atomic force microscope (NanoScope Atomic Force Microscope).

[0048] Preferably, it is less than 3 nm.

[0049] The first dielectric, with which the first electrode is at least partially covered, preferably has a dielectric strength Ed of 20 kV / mm to 30 kV / mm at a thickness of 1 mm. Such a dielectric strength enables the formation of a high-intensity electric field and thus a stable, long-burning plasma.

[0050] A typical measurement of the breakdown capacity is performed using a piece of glass with parallel surfaces and applied electrodes of typically about 4 cm. 2 The dielectric strength is determined using a DC voltage on the order of IkV / s and a sample thickness of 1 mm. The dielectric strength follows a Weibull statistic, and approximately 30 samples must be penetrated for the determination; the statistic must then be evaluated. A lower dielectric strength could lead to damage to the glass.

[0051] The first dielectric, with which the first electrode is at least partially covered, preferably has a coefficient of thermal expansion CTE20-300 of 2.5 x 10' 6 / K up to 12 x 10' 6 / K, preferably up to 9.5 x 10' 6 / K, especially preferred up to < 9 x 10' 6 / K. Especially with CTE20-300 > 4 x 10' 6 The thermal expansion behavior of the / K electrode is thus well adapted to the electrode material, which is, for example, stainless steel. This also applies to CTE20-300 < 4 x 10' 6 / K the difference in dimensions is sufficiently small. 04.08.2025

[0052] The property profile of the preferably disk-shaped first dielectric according to the invention, or the preferred profile described above, and thus of the device for generating low-temperature plasma, can preferably be represented by the fact that the glass of the first dielectric, which comprises a glass and is preferably disk-shaped, is a borosilicate glass, an alkali-free aluminosilicate glass, an alkali silicate glass, or a lithium aluminosilicate glass. It is particularly preferred that the first dielectric is a borosilicate glass. Preferably, the first dielectric consists of borosilicate glass.

[0053] Preferably the glass contains in wt.% an oxide-based

[0054] SiO271 - 83

[0055] B2O3 9 - 25

[0056] AI2O3 1 - 5

[0057] Li2O 0 - 1

[0058] Na2O + K2O 1 - 9

[0059] MgO 0 - 2

[0060] CaO 0 - 3

[0061] SrO 0 - 2 or

[0062] SiO249 - 62

[0063] B2O3 10 - 15

[0064] AI2O3 11 - 18

[0065] MgO 0 - 3

[0066] CaO 0 - 5

[0067] BaO 3 - 25 or

[0068] SiO263 - 71

[0069] B2O3 0 - 9

[0070] AI2O3 0 - 5

[0071] Na2O 5 - 9

[0072] K2O 5 - 9

[0073] CaO 0 - 7 04.08.2025

[0074] BaO 0-3 or

[0075] SiO262 - 68

[0076] B2O3 1 - 8

[0077] AI2O316-21

[0078] Li2O 3 - 6

[0079] Na2O 0-7

[0080] K2O 0-2

[0081] MgO 0 - 2

[0082] CaO 0 - 5

[0083] Preferably the glass contains in mol% on an oxide basis:

[0084] SiO274 - 85

[0085] B2O38-25

[0086] AI2O30.5 -4

[0087] Li2O 0 - 1

[0088] Na2O 1 - 5

[0089] K2O 0.3 - 2

[0090] MgO 0-3

[0091] CaO 0-3 or

[0092] SiO262 - 70

[0093] B2O39 - 16

[0094] AI2O37- 12

[0095] MgO 3 - 6

[0096] CaO 4 - 7

[0097] BaO 1 - 13 order

[0098] SiO265 - 75

[0099] B2O36-9

[0100] AI2O30 — 4

[0101] Na2O 5 - 9 04.08.2025

[0102] K2O 4 - 6

[0103] CaO 0-8

[0104] BaO 0-2 order

[0105] SiO265 - 71

[0106] B2O30 - 7

[0107] AI2O310 - 13

[0108] Li2O 7 - 12

[0109] Na2O 0.5 - 7

[0110] K2O 0.1 - 0.7

[0111] MgO 0-3

[0112] CaO 0-5

[0113] If the glass is a borosilicate glass, it preferably contains at least 9 wt.% boron oxide, at least 1 wt.% aluminium oxide and at least 71 wt.% silicon oxide.

[0114] Preferably it comprises, in wt.%, oxide-based:

[0115] SiO271-83

[0116] B2O39-25

[0117] AI2O31 - 5

[0118] Li2O + Na2O + K2O 0 - 1 - 10

[0119] MgO + CaO + SrO + BaO 0-7

[0120] If the glass is an alkali-free aluminosilicate glass, it preferably contains at least 11 wt.% aluminum oxide and at least 49 wt.% silicon oxide.

[0121] Preferably it contains in wt.% oxide-based:

[0122] SiO249 - 62

[0123] B2O3 10-15

[0124] AI2O311-18

[0125] MgO + CaO + SrO + BaO 3 - 25 08 / 04 / 2025

[0126] The term "alkali-free" means that it contains no alkali oxides or at most 0.1 wt.%, preferably at most 0.05 wt.%, or alkali oxide oxides.

[0127] If the glass is an alkali silicate glass, it preferably contains at least 63 wt.% silicon oxide and at most 9 wt.% boron oxide.

[0128] Preferably it contains in wt.% on an oxide basis:

[0129] SiO263 - 71

[0130] B2O3 0 — 9

[0131] AI2O3 0 - 5

[0132] Li2O + Na2O + K2O 5 - 18

[0133] MgO + CaO + SrO + BaO 0 - 10

[0134] A subgroup of alkali silicate glasses are the soda-lime glasses. If the glass is a soda-lime glass, it preferably has a coefficient of thermal expansion CTE20-300 between 7 x 10⁻⁶. 6 / K and 12 x 10' 6 / K on, preferably between 8.5 x 10' 6 / K and 9.5 x 10' 6 / K, up.

[0135] If the glass is a lithium aluminosilicate glass, it preferably contains at least 62 wt.% silicon oxide and at least 16 wt.% aluminum oxide and at least 3 wt.% lithium oxide.

[0136] Preferably it contains in wt.% on an oxide basis:

[0137] SiO262 - 68

[0138] B2O3 1 - 8

[0139] AI2O3 16 - 21

[0140] Li2O + Na2O + K2O 3 - 15

[0141] MgO + CaO + SrO + BaO 0 - 7

[0142] The first dielectric in the device according to the invention for generating low-temperature plasma, or the dielectric according to the invention, is preferably disk-shaped. The terms disk-shaped and plate-shaped are used synonymously in this disclosure. 04.08.2025

[0143] The term glass pane or plate is used in the present disclosure to refer both to a pane comprising glass and to a pane consisting of glass.

[0144] The person skilled in the art knows the individual components of the device for generating low-temperature plasma and how to manufacture the device for generating low-temperature plasma from them.

[0145] The dielectric, formed as a glass sheet, can be produced by conventional melting and hot forming processes. Suitable hot forming processes include, in particular, drawing processes such as up-draw, down-draw, especially overflow fusion, or float forming. Production using the float forming process is preferred. A person skilled in the art knows how to carry out the hot forming process in such a way as to obtain glass sheets with the desired properties with regard to low warping, low thickness variation (TTV), and low roughness (Ra). For example, DE 10 2017 101 808 Al describes a method for reducing thickness variation.

[0146] Examples:

[0147] The tables list various properties for example discs made of Al to A4 for use as a dielectric in a device for generating low-temperature plasma.

[0148] In the embodiment Al, this is a borosilicate glass with a coefficient of thermal expansion CTE20-300 of 3.3 x 10'. 6 / K. It contains approximately 80 wt% SiO2, approximately 2.5 wt% Al2O3 and approximately 13 wt% B2O3.

[0149] In embodiment A2, the glass is a borosilicate glass with a coefficient of thermal expansion CTE20-300 of 4.1 x 10'. 6 / K. It contains approximately 78 wt% SiO2, approximately 2.5 wt% Al2O3, and approximately 10 wt% B2O3. 04.08.2025

[0150] In embodiment A3, this is an alkali silicate glass with a coefficient of thermal expansion CTE20-300 of 9.4 x 10'. 6 / K. It contains approximately 70 wt% SiCh, approximately 7 wt% CaO and approximately 16 wt% Na₂O + K₂O.

[0151] In embodiment A4, this is a lithium aluminosilicate glass with a coefficient of thermal expansion CTE20-300 of 5.5 x 10'. 6 / K. It contains approximately 67 wt. % SiO2, approximately 4 wt. % B2O3, approximately 17 wt. % Al2O3 and approximately 4 wt. % Li2O.

[0152] The lenses Al, A2 and A4 are manufactured using the float process. The lens A3 is manufactured using the down-draw process.

[0153] Disc-shaped samples of them exhibited the following properties, which are listed in the tables:

[0154] Warp [pm]: measured perpendicular to the drawing direction of the hot forming process, possibly differentiated between 1. measured on a sample from the center of the drawn glass ribbon and 2. measured on a sample from the edge area of ​​the drawn glass ribbon.

[0155] Thickness variation “TTV” [pm]; measured transversely to the drawing direction of the hot forming process, possibly differentiated between 1. measured on a sample from the center of the drawn glass ribbon and 2. measured on a sample from the edge area of ​​the drawn glass ribbon.

[0156] Surface roughness Ra [nm], measured with an atomic force microscope (NanoScope Atomic Force Microscope)

[0157] A measuring table from IC-Automation GmbH was used for the warp measurement. It was a granite table. Chromatic and interferometric sensors were used for the position measurement.

[0158] The thickness variation of the glass ribbon was determined using the double reflection method. A thin laser light line was projected onto the glass. The laser beam was reflected from the front and back of the glass ribbon. The two reflections were imaged onto a line sensor. The thickness measurement was calculated from the distance between the two reflections. The device contained two identical but opposing beam paths. This increased the accuracy of the measurement and reduced the measurement error (04.08.2025) due to tilt and / or wedge-shaped distortion. The measurements in both channels of the measuring head were performed sequentially in rapid succession at intervals of approximately 1 ms.

[0159] Table 1 contains information on Warp, TTV and Ra for the embodiments Al and A2 for samples with a format of 460 mm x 430 mm and a thickness of 1.1 mm.

[0160] Table 1: Table 2a and Table 2b contain the embodiments Al, A2 and A4.

[0161] Warp and TTV data for samples measuring 460 mm x 430 mm x 0.7 mm.

[0162] Table 2a: Table 2b: August 4, 2025

[0163] Table 3 contains information on warp and TTV for the embodiments Al and A3 for samples with dimensions of 390 mm x 560 mm x 0.9 mm.

[0164] Table 3:

[0165] The glasses according to the embodiments exhibit, on an area of ​​1150 mm x 850 mm and a thickness of 1 mm, a warp of at most 300 pm, a thickness variation (TTV) of at most 40 pm and a roughness (Ra) of less than 5 nm.

[0166] All these values ​​demonstrate the ability of such disks to form a narrow and dimensionally accurate plasma gap as dielectric barriers, thereby enabling the device for generating low-temperature plasma in which they are installed to produce a homogeneous plasma.

[0167] If, as can be seen in embodiments Al and A2, the warping differs depending on the origin of the disk in the glass ribbon, it is preferred to take this into account when aligning the dielectrics of opposing electrodes so that, as already described for the preferred dished arrangement, existing warps cancel each other out and do not increase.

[0168] The first dielectric, comprising or consisting of glass, as described, serves as a component of a device for generating low-temperature plasma. The invention therefore relates not only to the device for generating 04.08.2025

[0169] low-temperature plasma with such a first dielectric, but also the dielectric itself, i.e., the glass disk suitable for use as a dielectric in a device for generating low-temperature plasma, as well as its use in the device for generating low-temperature plasma.

[0170] Preferably, the glass sheet for use as a dielectric in a device for generating low-temperature plasma has a size of 90 mm x 60 mm to 500 mm x 500 mm. An advantage of the invention is that the dimensional accuracy of the dielectric can be achieved directly through the primary shaping process, rather than through subsequent processing, e.g., polishing, which simplifies the manufacturing process of both the dielectric and the device.

Claims

August 4, 2025 Patent claims:

1. Device for generating low-temperature plasma comprising a first dielectric comprising a glass, preferably made of glass, a first electrode which is at least partially covered with the first dielectric, a plasma source, a discharge chamber, an electrical energy source, a second dielectric, a second electrode which is at least partially covered with the second dielectric, wherein the electrodes are arranged such that a predetermined gap separates the first and the second dielectric, wherein the glass-comprising first dielectric has a thickness of at most 1.5 mm and, at a thickness of 1 mm over an area of ​​1150 mm x 850 mm, has a warpage of at most 300 pm, a thickness variation of at most 40 pm, and a roughness of less than 5 nm.

2. Device according to claim 1, characterized in that the first dielectric comprising the glass, preferably consisting of glass, has a dielectric strength Ed of 20 kV / mm to 30 kV / mm at a thickness of 1 mm.

3. Device according to claim 1 or 2, characterized in that the first dielectric comprising the glass, preferably consisting of glass, has a warpage of at most 200 pm and / or a thickness variation of at most 30 pm, preferably at most 15 pm, particularly preferably at most 5 pm and / or a roughness of less than 3 nm. August 4, 2025 4. Device according to one of claims 1 to 3, characterized in that the first dielectric comprising the glass, preferably consisting of glass, has a thickness of less than 1 mm, preferably of at most 0.7 mm.

5. Device according to one of claims 1 to 4, characterized in that the glass of the glass-comprising, preferably glass-composing, first dielectric is a borosilicate glass or an alkali-free aluminosilicate glass or an alkali silicate glass or a lithium aluminosilicate glass.

6. Device according to one of claims 1 to 5, characterized in that the glass of the first dielectric comprising glass, preferably consisting of glass SiO271 - 83 B2O3 9 - 25 AI2O3 1 - 5 Li2O 0 - 1 Na2O + K2O 1 - 9 MgO 0 - 2 CaO 0 - 3 SrO 0 - 2 or SiO249 - 62 B2O3 10 - 15 AI2O3 1 1 - 18 MgO 0 - 3 CaO 0 - 5 BaO 3 - 25 or SiO263 - 71 B2O3 0 - 9 AI2O3 0 - 5 August 4, 2025 Na2O 5 - 9 K2O 5 - 9 CaO 0 - 7 BaO 0 - 3 or SiO262 - 68 B2O31 - 8 A12O316 - 21 Li2O 3 - 6 Na2O 0 - 7 K2O 0 - 2 MgO 0 - 2 Contains CaO 0 - 5 in mol-% on an oxide basis.

7. Use of a glass disc as a dielectric for a device for generating low-temperature plasma according to any one of claims 1 to 6.

8. Use of a glass pane according to claim 7, wherein the glass pane has a format of 90 mm x 60 mm to 500 mm x 500 mm.

9. Glass sheet for use as a dielectric in a device for Generation of low-temperature plasma according to any one of claims 1 to 6.

10. Glass pane according to claim 9 with a format of 90 mm x 60 mm to 500 mm x 500 mm.

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