KR20210133877A - Cover panel, method for producing same, and use thereof - Google Patents

Abstract

The present invention generally relates to a cover panel, a method for producing the cover panel, and a use thereof. The present invention has resistance at high temperatures.

Description

COVER PANEL, METHOD FOR PRODUCING SAME, AND USE THEREOF

The present invention relates generally to cover panels, methods for producing such cover panels and uses thereof.

A cover panel is used, for example, for furniture, in which case the cover panel separates the area in which the electronic component is arranged, for example from the user area. For example, the cover panel may also be used as a so-called hot plate or cooking panel of a cooking appliance. Another area of application of the cover panel is, for example, the use of the cover panel as a fireplace viewing window in an oven or fireplace or other heating device.

Accordingly, the cover panel may generally be exposed to significant thermal loads during operational use.

However, it has been found over and over again that the mechanical loads subjected to cover panels during use can also be significant. For example, the load may include on the surface of such a cover panel and/or of, for example, a coating such as a so-called decorative layer used to mark a so-called functional zone of a cooking panel or of other coatings provided on the surface of the cover panel. includes wear or scratch loads that can cause significant wear and tear.

It should also be borne in mind that chemical resistance as well as wear resistance such as heat resistance of the material and hardness of the layer are important. Indeed, when the cover panel is used as a viewing window or cooking surface in, for example, a high-temperature application, such as an oven or fireplace, aggressive substances may come into contact with the cover panel, in particular also at higher temperatures.

In particular, in order to improve the abrasion resistance of the surface of such a cover panel, a so-called scratch protection layer has been applied, in particular, to the surface of the cover panel. However, it has been found that it is still difficult to obtain a coating that is sufficiently hard and exhibits sufficient chemical resistance even at high temperatures. In addition, the material of the scratch protection layer should moreover be as visually inconspicuous as possible. That is, the cover panel should, as far as possible, not manipulate the color of the light passing through the cover panel and/or as low absorptivity as possible so that, for example, a light indicator, such as a display, can still be easily recognized even in relatively low illuminance. should only indicate

Suitable materials for the wear protection layer include, for example, metal nitrides or carbides, for example nitrides or carbides of aluminum or titanium, or semimetals such as silicon. However, these materials are not sufficiently chemically resistant for use at high temperatures.

Other materials considered, at least in principle, for the scratch protection layer are oxides, in particular metal oxides. It is also a very stable material, some of which are transparent or colorless. However, oxides, in terms of their mechanical properties, are mostly inferior to the considerably harder carbides and nitrides. Some single metal metal oxides, that is, metal oxides containing only one metal as a main metal component, have a disadvantage in that they are colored like iron oxide or chromium oxide. Titanium dioxide, on the other hand, is colorless but has a very high refractive index, so it reflects visible light so strongly that it makes these coatings more visually appealing.

Alternative materials contemplated include metallic mixed oxides, in particular bicomponent or bimetallic oxides.

In the context of the present disclosure, "metal mixed oxide" is understood to mean an oxide comprising a plurality of metallic components as a main component. In other words, the metal mixed oxide includes an oxygen ion (O ^{2 -} ) as an anion and a cation of at least two elements, in particular, a cation of at least two metals, and the second metal contained in the mixed oxide is a dopant or only an unavoidable trace amount. It is an essential component, not a form of

A bimetallic or bicomponent metal oxide or mixed oxide is understood to mean an oxide comprising two metals as main components. The term bimetallic or bicomponent metal oxides or mixed oxides includes, inter alia, _{oxides or mixed oxides having a spinel structure of the general formula AB 2} 0 ₄ , which in the context of the present disclosure are referred to as “oxides having a spinel structure” The word includes oxides or mixed oxides that crystallize in a spinel structure as well as oxides that crystallize in an inverse spinel structure.

In a structure known as a spinel structure or inverse spinel structure, the metal cations are located in the interstices of the dense packing of the same spheres as defined by the oxygen ions according to their size. The spinel structure (as well as the so-called inverted spinel structure) is a crystal structure known to those skilled in the art and is named after the _{MgAl 2} O _{4 mineral spinel.}

A spinel, MgAl ₂ O _{4 ,} is particularly important here, since it can withstand temperatures up to 1000° C. and higher and, in particular, has sufficient chemical resistance. Moreover, it is known that this material can still be transparent even at a thickness of several centimeters and that very rigid bodies can be obtained from spinel.

As materials based on spinel, for example, ceramics are known. For example, in 1969, Gatti, A., of General Electric, Philadelphia, Pennsylvania, published a final report entitled "Development of a process for producing transparent spinel." bodies)" describes a method for producing transparent bodies from spinel.

In addition, EP 0 334 760 B1 describes a process for producing high-performance objects from magnesium-aluminum spinel, in particular transparent objects in the infrared and visible range.

US patent document US 4,029,755 A describes a ceramic which is transparent and obtained by a cold pressing process, which ceramic consists of fine particles having a diameter of 50 μm to 300 μm during the ceramic process.

Also, as disclosed in EP 3 502 075 A1, a black coating comprising a material having a spinel structure has already been obtained.

However, it is not yet possible to obtain a transparent and colorless coating on the cover panel which is useful as a scratch protection layer so far. In fact, the layer of EP 3 502 075 A1 is a colored coating and has only a very small thickness of several hundred nm, since, ultimately, a sufficient transmittance in the infrared range of the electromagnetic spectrum must still be ensured despite the coloring of the coating due to absorption. Layers of the prior art are therefore not suitable as scratch protection layers, in particular as colorless scratch protection layers, since the material according to EP 3 502 075 A1 contains transition metal ions and will therefore always have a distinct intrinsic color.

There is therefore a need for cover panels and methods for producing such cover panels, which are transparent and have a coating that is mechanically and/or chemically resistant, preferably even at high temperatures of up to 1000°C.

It is an object of the present invention to provide a cover panel which at least partially overcomes or at least alleviates the prior problems of the prior art.

The objects of the invention are achieved by the subject matter of the independent claims. Preferred and/or more specific embodiments will become apparent from the dependent claims.

Accordingly, the present invention provides a cover comprising a glass or glass ceramic substrate having a first major surface and a second major surface and a coating disposed on at least one of the major surfaces of the glass or glass ceramic substrate in at least one region of the cover panel. relates to a panel, the coating including at least one mixed oxide of the formula a _x B _y O _4, or exceeds mainly, that is, 50% by weight of at least one mixed oxide of the formula a _x B _y O _4, or formed substantially, i.e., greater than or equal to 90% by weight, wherein the molar ratio of A to B is from 0.3 to 0.7 and the mixed oxide and/or coating is at least partially crystalline, in particular polycrystalline, wherein A is Preferably, it comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, B preferably comprises Al, Fe, Cr, V or mixtures thereof, the coating is preferably In some cases, it exhibits a light transmittance exceeding 70%.

In the context of this disclosure, the following definitions should apply.

In the context of the present disclosure, a panel is understood to mean a shaped body whose dimension in one spatial direction of the Cartesian coordinate system is at least one order of magnitude smaller than in two other spatial directions perpendicular to the first spatial direction. In other words, the thickness of the molded body is smaller than the length and width.

In the context of the present disclosure, a major surface of a panel or more generally of a shaped body is understood to mean the surface of a shaped body or panel comprising a majority of the surface area of the surface of the shaped body or panel. In the case of panels, in particular, the major surface is a surface whose dimensions are defined by the length and width of the shaped body. Depending on the exact arrangement of the panel, the major surfaces are often referred to as the top and bottom surfaces of the panel or the front and back surfaces.

The embodiment of the cover panel as described above has many advantages.

Coating comprises a mixed oxide of the formula A _x B _y O _4, or, primarily, that is, 50% by weight (or at.%, That is, based on the respective molar fraction of at least one mixed oxide of the formula A _x B _y O ₄ ), or substantially, ie more than 90% by weight, or wholly formed means on the one hand that the coating is stable at high temperatures. In the context of the present disclosure, a stable design at high temperatures of a coating and/or material is understood to mean that at high temperatures, such as at most temperatures below 900°C, in particular at most 800°C, the material or coating will not undergo a phase change. Also, the material or coating will not show any degradation such as decomposition reactions or cracking.

This very good resistance of the material and thus of the coating is advantageously promoted by the fact that the mixed oxide and/or the coating is at least partially crystalline. For example, the mixed oxide may be in the form of a spinel structure or inverse spinel structure or otherwise in the form of an olivine structure, the presence of a spinel structure or optionally an inverted spinel structure may be advantageous. This is because the spinel structure, or optionally the inverse spinel structure, is a very stable structure in terms of crystallography and does not tend to undergo a phase change. Therefore, it is particularly advantageous if the content of crystals or grains in the coating is very high. The material or coating or mixed oxide is, in particular, polycrystalline.

The advantageous implementation of the coating may, in particular, be influenced by the choice of material. Accordingly, component A is preferably composed of iron (Fe) and/or magnesium (Mg) and/or beryllium (Be) and/or zinc (Zn) and/or cobalt (Co) and/or silicon (Si) and and/or manganese (Mn) and/or vanadium (V) and/or mixtures thereof. It is preferred that the metal defining component A or comprised in component A is preferably present in the form of a cation having an oxidation number II+, ie, for example an alkaline earth metal. However, component A may also be formed by or comprise silicon, which is a semimetal having an oxidation number IV+ in an oxidizing compound. More preferably, B comprises aluminum (Al), iron (Fe), chromium (Cr) or vanadium (V) or mixtures thereof, wherein the metal defining component B or contained in component B is in the form of a cation exist. It is particularly preferred when the majority of A (ie at least 50 atomic % or mol %) is magnesium and the majority (ie at least 50 atomic % or mol %) of B is aluminum. In particular, with the exception of unavoidable traces, it is also possible for the material or mixed oxide or coating to contain as metallic components only magnesium and aluminum or their cations, ie the material or mixed oxide or coating is spinel MgAl ₂ O ₄ , in particular It is possible to form into polycrystalline spinel. In particular, polycrystalline embodiments of materials and/or coatings may be advantageous, since the presence of very small and fine grains is not visually conspicuous as grain boundaries are not perceived as visually obstructive, and thus , the transparency or visibility through the coating is not significantly impaired.

The following metal combinations are preferred.

When A comprises magnesium and/or beryllium, B is preferably aluminum and/or iron and/or chromium and/or vanadium.

When B comprises aluminum, A is preferably a mixture of magnesium and/or beryllium and/or magnesium and/or beryllium and/or vanadium.

When B comprises chromium, A is preferably magnesium and/or iron and/or zinc and/or cobalt.

When B comprises vanadium, A is preferably manganese and/or magnesium.

When B comprises iron, A is preferably magnesium and/or silicon.

According to one embodiment, the coating thus has a molar ratio of A to B of at least 0.3 and no more than 0.7, wherein A comprises magnesium and/or beryllium, and B comprises aluminum and/or iron and/or chromium and/or vanadium. at least one mixed oxide of the formula A _x B _y O _{4 comprising}

And and / or A-to-B molar ratio is more than 0.7 more than 0.3 in, B has the formula A _x B which comprises aluminum, A contains a magnesium and / or beryllium and / or the mixture of magnesium and beryllium, and / or vanadium, at least one mixed oxide of _y O _{4 ,}

And and / or A-to-B molar ratio is more than 0.7 more than 0.3 of the, B comprises aluminum, B is a formula A _x containing chromium and A contains a magnesium and / or iron and / or zinc and / or cobalt, at least one mixed oxide of B _y O _{4 ,}

and/or at least one mixed oxide of _{the formula A x} B _y O ₄ wherein the molar ratio of A to B is from 0.3 to 0.7, B comprises vanadium and A comprises manganese and/or magnesium;

and/or at least one mixed oxide of _{formula A x} B _y O ₄ wherein the molar ratio of A to B is 0.3 to 0.7 and B comprises iron and A comprises magnesium and/or silicon.

Here, it is possible for the coating to comprise only one crystalline phase, for example crystals or grains comprising or formed of _{MgAl 2} O _{4 .} It is synonymous with a coating comprising only one mixed oxide or consisting mainly or substantially or entirely of only one mixed oxide. However, it is also possible for the coating to comprise a plurality of crystalline phases, eg _{Fe 2} SiO ₄ and/or other crystalline phases in addition to _{, for example, MgAl 2} O _{4 .} This is synonymous with a coating comprising a plurality of mixed oxides or consisting mainly or substantially or even entirely of a plurality of mixed oxides.

More generally, it is also possible for the coating to be at least partially amorphous, ie comprising an amorphous phase in addition to at least one crystalline phase or possibly a plurality of crystalline phases.

An embodiment of a coating comprising only one crystalline phase (or comprising only one mixed oxide) is understood to mean that the coating comprises only crystals or grains of one particular crystallographically determinable phase. Accordingly, an embodiment of a coating comprising a plurality of crystalline phases is understood to mean that different crystalline phases can be detected crystallographically in the coating, for example by means of X-ray diffraction (XRD).

Preferred crystalline phases are, for example, MgAl ₂ O ₄ , BeAl ₂ O ₄ , MgFe ₂ O ₄ , MgCr ₂ O ₄ , MgV ₂ O ₄ , (Be, Mg)Al ₂ O ₄ , eg BeMgAl ₄ O ₈ , FeCr ₂ O ₄ , ZnCr ₂ O ₄ , CoCr ₂ O ₄ , FeV ₂ O ₄ , Val ₂ O ₄ , SiFe ₂ O ₄ , MnV ₂ O ₄ .

Furthermore, advantageous realization of the coating properties may also be facilitated by appropriate selection of the molar ratios of components A and B to each other. The molar ratios of components A and B to each other are advantageously in the range from 0.3 or more to 0.7 or less. In particular, it is possible for this ratio to be exactly 0.5, ie one atom A for every two atoms B. In this case, a stoichiometric composition according to the spinel structure or the inverse spinel structure AB ₂ O _{4 results.} However, deviations from these ideal stoichiometric ratios are allowed within the limits described above and may be based, for example, on valence changes of components A and/or B. In particular, it is also possible in principle for the mixed oxide to comprise component C in addition to component A and/or component B, ie the mixed oxide A _x B _y O ₄ can be doped. Since components A and B determine the essential properties of the oxide, it can still be said as a _{compound or mixed oxide A x} B _y O _{4 .} In the case of doped mixed oxides, if component C is to be mentioned, mixed oxides may also be denoted or designated as _{A x} B _y O ₄ or A _x B _y C _z O _{4 .} Here, in general, without being limited to any one of the embodiments of mixed oxides, coatings and/or cover panels, the amount of oxygen (O) depends on the valence and/or amount of components A, B and/or C present in the formula It is understood that it may differ slightly from the stoichiometric amount indicated in (i.e., index "4"). However, this is considered insignificant as long as the crystal structure still matches the crystal structure of the stoichiometric compound in question.

In particular, the scratch protection of the prior art, such as nitrides, although the formation of an oxidizing phase of the _{formula A x} B _y O ₄ is advantageous because coatings with abrasion resistance, for example scratch and/or abrasion resistance, can be obtained in this way. It shows the stress reduction of the layer compared to the coating. The absolute value of the layer stress of the coating according to the embodiment is preferably at most 800 MPa, more preferably at most 500 MPa, and most preferably at most 300 MPa. That is, the layer stress is preferably ±800 Mpa, more preferably at most ±500 MPa, and most preferably ±300 MPa or less. This means that depending on the precise embodiment, the coating may be subjected to tensile stress or compressive stress. This also enables, for example, the coating of very thin substrates, eg thin glass, since, due to the reduced layer stress, in particular one side coated with the coating according to an embodiment of the present disclosure This is because even a thin coated substrate will show only slight warpage.

The reduced stress of the coating material layer according to embodiments of the present disclosure is also advantageous during the coating process. In fact, as a result of the high intrinsic layer stress of the nitride, a layer formed of such a coating material often tends to peel off at the inner surface of the coating unit, ie inside the sputter deposition chamber, for example.

According to an embodiment of the cover plate, the cover plate is embodied such that the absolute value of the layer stress of the coating according to the embodiment is at most 800 MPa, preferably at most 500 MPa, and most preferably at most 300 MPa.

The layer stress of an oxidation and/or nitridation system can be affected by a number of process parameters. Parameters that play a particularly important role are those influencing the porosity, packing density, crystalline state and/or the layer structure of the coating. Parameters that should be mentioned here are in particular process pressure and temperature. Also, the effect of temperature is highly dependent on the coated material and its phase transition. Although no general rule can be drawn in this regard, it can also be expected that the temperature will also have a strong effect on the layer stress due to the effect on the porosity and crystalline state of the layer. In addition, the stress of the coating may arise due to differences in the coefficients of thermal expansion, for example between the linear coefficients of thermal expansion of the substrate and the layer materials, which may have already been triggered as a result of the cooling process subsequent to the coating process.

Process pressure is another important parameter for tuning the layer stress. In most cases, low pressure leads to reduced voids and compact layer growth, often resulting in increased compressive stress. This can be seen, for example, in sputter deposited Si ₃ N _{4 coatings.} That is, in this case, the low process pressure is very high with absolute stress values exceeding 2 GPa at most, as can be seen, for example, in FIG. 8 on page 158ff of the thin solid film 351 (1999) of Ruske et al. resulting in layer stress.

Here, the crystalline state of the coating includes parameters related to the crystallinity of the coating, such as the type, number and/or size of crystalline phases included in the coating.

Surprisingly, it has been found that a method according to an embodiment of the present disclosure allows the acquisition of a layer exhibiting a relatively low layer stress, as will be described in more detail below, providing the advantages discussed above.

In addition, the oxidizing material included in the coating according to embodiments of the present disclosure may have a refractive index lower than, for example, a nitric acid material or more generally a prior art scratch protective coating, i.e., 1.6 to 1.8, for example, 1.7. has This is advantageous because in this way the visibility of the coating according to the embodiment of the present disclosure is lower, in particular than in conventional scratch protective coatings. In particular in the case of cover panels comprising colored glass or glass ceramic substrates, or in the case of glass or glass ceramic substrates provided with an additional coating on the major surface opposite to the major surface on which the coating is disposed, the additional coating has a masking effect, More generally, by reducing the transparency of the substrate, coatings according to embodiments of the present disclosure are barely noticeable visually.

The coating preferably exhibits a light transmittance of greater than 70%. Preferably, the light transmittance of the coating is at least 80%, most preferably at least 90%. The light transmittance of the coating determines the light transmittance of the uncoated substrate, determines the light transmittance of the substrate in the region where only the coating is disposed on only one major surface of the glass or glass ceramic substrate, and then from the value of the coated substrate the light transmittance of the uncoated substrate is determined. It is determined by calculating the difference between the light transmittances in such a way as to subtract the value obtained for the substrate. Consequently, a decrease in transmittance is caused by the coating. The light transmittance resulting from the coating is the difference determined from the light transmittance of the coated and uncoated substrates minus 100%, as described above. The light transmittance of the coated and uncoated substrates is preferably determined according to or on the basis of DIN EN ISO 13468 for a wavelength range of 380 nm to 780 nm.

For example, if the light transmittance of the coated substrate is 76% and the light transmittance of the uncoated substrate is 77% in a region where only the coating is disposed on only one major surface of the substrate, the resulting difference in light transmittance of the substrate is 1% am. Thus, the light transmittance of the coating is in this case 100% minus 1%, ie 99%.

In other words, the light transmittance of the coating is calculated according to the following equation.

Here, LT means light transmittance, and the light transmittance of the coated substrate is the light transmittance of the cover panel in a region consisting of only the substrate and the coating. Here, the light transmittance of the coated substrate and the light transmittance of the uncoated substrate are preferably determined according to or on the basis of DIN EN ISO 13468 for a wavelength range of 380 nm to 780 nm.

This implementation in which the light transmittance of the coating is as high as 70% or more is advantageous since the visibility through the coating is not significantly reduced in this way. Therefore, such high light transmittance is particularly desirable for observation window applications. However, it may be advantageous to implement the coating, for example, as a highly transparent coating, even in the case of applications where, for example, the coating is applied to an already coated substrate. Other coatings, such as, for example, where a coating according to an embodiment of the present disclosure is a "topcoat," will be clearly recognized through a coating according to an embodiment of the present disclosure. This is particularly advantageous if an additional coating is provided, for example in the form of a logo.

According to an embodiment of the present disclosure, the coating has a thickness of at least 0.05 μm and preferably at most 3 μm. Such a minimum layer thickness is advantageous because it improves the mechanical stability of the coating. Here, the mechanical stability of the coating is the property of the coating to resist wear and tear, such as scratches or abrasion. Surprisingly, advantageous properties of the coating can already be achieved with a layer thickness of 50 nm. Increasing the layer thickness of the coating can further improve the mechanical properties of the coating. However, it is particularly advantageous to limit the layer thickness to preferably 3 μm or less. This is because the mixed oxides that may be included in the coating may have a unique color in some cases. This intrinsic color appears especially when the mixed oxide in question is provided in the form of a bulk material. However, the situation is different when a material having an intrinsic color as a bulk material is provided in the form of a thin coating. In this case, the coating may exhibit only very slight color and no intrinsic color of the mixed oxide may be perceived. Therefore, the coating should not be too thick as a thicker coating is more visually striking than a thinner coating and more prone to cracking. Moreover, it is not cost effective to produce coatings that are too thick, particularly in the μm range, since thick coatings may also reduce the breaking strength of the cover panel, such as, for example, impact resistance or flexural strength. Therefore, it is desirable that the thickness of the coating be limited. Preferably, the thickness is 3 μm or less.

According to a further embodiment of the present disclosure, the coating is transparent and colorless. This is advantageous because in this way the coating is not visually noticeable to a certain extent. This ensures that the coating preferably only slightly reduces the light transmission through the glass or glass ceramic substrate, but most preferably that the coating itself does not cause a change in the color position of the light transmitted through the glass or glass ceramic substrate. In other words, a luminous indicator, for example a display arranged under or behind such a cover panel, can be perceived in this way and/or with a particularly accurate color without requiring a particularly strong luminous intensity.

The optical properties of the coating according to the transparent and colorless embodiment may preferably be characterized by a comparison of the color positions of an uncoated glass or glass ceramic substrate and a glass or glass ceramic substrate coated with a coating according to the embodiment. . _{Accordingly, in the context of the present disclosure, the color position E 101} of the cover panel in the portion where only the coating is disposed on only one major surface of the glass or glass ceramic substrate is the region where the coating is not disposed on the glass or glass ceramic substrate. If there is a difference between the color position (E ₁₁₀ ) of the cover panel at and most preferably, the color position in the part (E ₁₁₀ ) and the color position in the region (E ₁₀₁ ) are determined in the L*a*b* color system, and the difference in color positions (ΔE) is It is calculated using the formula.

The color position (E ₁₁₀ ) is given by the color coordinates (a* ₁₁₀ , b* ₁₁₀ , L* ₁₁₀ ), and the color position (E ₁₀₁ ) is given by the color coordinates (a* ₁₀₁ , b* ₁₀₁ , L* ₁₀₁ ). These color positions are preferably determined from measurements on white tiles using, inter alia, a CM-700d spectrophotometer from Konica Minolta.

According to a further embodiment of the cover panel, the cover panel has a thickness of from 2 mm to 8 mm, preferably from 4 mm to 6 mm. This is advantageous because in this way the cover panel exhibits sufficient mechanical strength with respect to breaking loads in order to enable it to be used, for example, as a viewing window or cooking panel in high temperature applications. The mechanical strength of the cover panel to the breaking load includes, for example, so-called impact resistance, which can be determined through a test known as a ball drop test, and flexural strength, which can be determined, for example, in a three-point bending test. Here, in order to achieve sufficient strength of the cover panel, it is advantageous for the cover panel to have a thickness of at least 2 mm, preferably at least 4 mm. However, the cover panel should also not be too thick, since otherwise on the one hand the material cost is too high and on the other hand the weight of the cover panel is too high. Accordingly, the cover panel preferably has a thickness of at most 8 mm, preferably at most 6 mm. According to one embodiment, it is possible for the cover panel to comprise a substrate having a thickness of at least 2 mm, preferably at least 4 mm and with a thickness of at most 8 mm, preferably at most 6 mm.

However, according to a further embodiment, it is also possible for the cover panel to have a thickness of less than 2 mm, eg 1 mm or even smaller, eg 30 μm or more, such as 50 μm or 100 μm. Thus, according to an embodiment, in particular, it is possible for the cover panel to comprise a substrate in the form of a so-called thin glass. In particular, it is also possible for the substrate to have a thickness of less than 2 mm, for example less than or equal to 1 mm, for example greater than or equal to 30 μm, such as 50 μm or 100 μm. Surprisingly, this configuration is possible with the coating according to the embodiment, since the stress of the coating layer according to the embodiment is very low in the case of hard materials or layers known as anti-scratch or wear protection layers. This becomes particularly evident from the fact that the cover panel provided with this coating exhibits only slight warping.

According to another embodiment of the cover panel, the haze of the cover panel, measured according to ASTM D 1003, of the cover panel or glass or glass ceramic having only a coating disposed on only one major surface of the glass or glass ceramic substrate In a portion of the area of the substrate, less than 5%, preferably less than 2%, and most preferably less than 1%.

In other words, in a cover panel or a portion of a glass or glass ceramic substrate in which only a coating is disposed on only one major surface of the glass or glass ceramic substrate, the cover panel exhibits only very little haze, ie the cover panel is very clear. This is achieved in particular by the fact that the coating itself has only very low haze or does not show any significant haze. This embodiment is advantageous because in this way a particularly good visibility through the cover panel is ensured, so that a light emitting component disposed behind or under the cover panel, for example a display, can be easily recognized. This embodiment is also advantageous for viewing windows in high temperature applications such as oven or fireplace viewing windows.

According to a further embodiment of the cover panel, the coating has a hardness of 6 Gpa to 11 GPa determined in a measuring method conforming to or based on DIN EN ISO 14577-1 and -4 (also known as Martens hardness) has This design is particularly preferred, since in this way the cover panel exhibits particularly good abrasion resistance and tear resistance against scratches or abrasion of the surface in the area where the coating is provided. In other words, according to this embodiment, the cover panel is of a type having abrasion resistance, in particular scratching and/or abrasion resistance, at least in the region where the coating is disposed on the major surface of the glass or glass ceramic substrate. This is particularly important for applications where the cover panel is in contact with abrasive materials and/or articles. This embodiment of the cover panel is particularly advantageous in the cleaning process of so-called hot plates or observation windows for ovens or fireplaces, in particular when so-called scrapers are used for cleaning operations. However, contact with cookware may cause scratches on the surface, for example.

This embodiment is particularly advantageous for use in cover panels where frictional stresses may occur when the pot is moved, for example in the case of cooking panels. Again, it should be taken into account that, for example, abrasive particles may be present between the surface of the cooking panel and the cooking utensils, which will subsequently cause additional abrasive effects. Accordingly, cover panel constructions in which the coating also exhibits abrasion resistance as mentioned above are particularly advantageous, since it will reduce surface wear.

According to a particularly advantageous embodiment of the cover panel, the coating covers the major surface of the glass or glass ceramic substrate over substantially the entire surface area. In the context of the present disclosure, covering substantially the entire surface area is understood to mean that the coating covers at least 90%, preferably at least 95% of the area concerned. This embodiment is particularly advantageous if the coating exhibits high hardness and/or high wear resistance, since the major surface substantially completely covered by the coating covers almost the entire surface area, in particular wear resistance, eg abrasion resistance, because it will be resistant and/or scratch resistant. Coating over substantially the entire surface area is also understood to include implementations in which the coating according to an embodiment is not disposed directly on a major surface of the substrate, but in which a layer is provided between the substrate and the coating. Shielding is generally expressed as the ratio of the major surface area covered by the coating to the total surface area of the major surface.

According to a further embodiment of the cover panel, the cover panel comprises a further coating. This further coating may be, for example, a glass flux-based coating, obtained, for example, by printing so-called enamel paints and subsequently carrying out a firing treatment. Glass flux based coatings for cover panels are known. Such coatings are used, for example, as cooking zone markings and/or used to mark functional areas. This is particularly important, for example, especially in the case of cover panels used as cooking panels for so-called induction heaters, since it is important to mark the functional areas as it is only with the correct positioning of the cooking utensils that the cooking process is guaranteed to actually take place.

According to this embodiment of the cover panel, the further coating is disposed on the same major surface as the coating of the glass or glass ceramic substrate and at least partially or only partially covers this major surface. A further coating is disposed between the glass or glass ceramic substrate and the coating. In particular, the further coating preferably adjoins the coating.

This configuration of the cover panel may be particularly advantageous if the further coating is not particularly resistant mechanically and/or chemically. For example, it is known that materials in contact with the cover panel may attack the surface of the cover panel or glass or glass ceramic substrate. As discussed above, this may lead to mechanical wear, such as scratching and/or abrasion of the surface, but it is also possible for some materials to chemically react with the surface and degrade. In particular, it is also known that coatings applied to the surface of cover panels and/or glass or glass ceramic substrates, such as, for example, glass flux based coatings, are particularly susceptible to mechanical and/or chemical attack. This is because, for example, these glass flux-based coatings have insufficient adhesion to glass or glass-ceramic substrates, or because the surface of these glass flux-based colored coatings is very rough, providing a larger attack surface for both mechanical and chemical attack. This may be due to the fact that it provides In particular, in the case of cooking panels, it is also possible, for example, during operational use, to form an intimate bond with the glass flux-based tinted decoration due to food burning on the surface, ie the upper surface, of the cover panel facing the user during operational use. It is entirely possible for a part of the decoration to be removed together with dirt during cleaning, which is preferably carried out using a so-called scraper. Not only is this visually distracting, but it can even result in a significant portion of the important markings being removed from the functional area.

Thus, according to one embodiment of the cover panel, a further coating is disposed on the same major surface as the coating of the glass or glass ceramic substrate so as to at least or only partially cover the major surface, wherein the further coating is coated with the glass or glass ceramic substrate It is particularly preferred to be disposed between them. In this case, the further coating may be disposed directly on the major surface of the glass or glass-ceramic substrate, ie directly in contact with the glass or glass-ceramic substrate. For example, this may be advantageous if, for example, an intimate bond is formed between the material of the glass or glass ceramic substrate and the material of a further coating, such as a glass flux based coating, to create a molten reaction zone. However, in order to reduce the formation of so-called halos, for example around glass flux based coatings, another coating effective, for example, as an adhesion promoter or, for example, as a separation layer, can be combined with an additional coating and glass or glass ceramic. It is also possible to arrange between the surfaces of the substrates.

Advantageously, the coating is applied over the further coating. For this purpose, it is advantageous that adhesion failure does not occur at the interface between the coating and the further coating if the coating adheres well to the further coating. In fact, when a coating is applied over an additional coating, the coating serves as a protective coating and a type of topcoat for the additional layer, and thus can also simultaneously improve the mechanical and/or chemical resistance of the additional coating.

According to a further embodiment of the cover panel, the glass or glass ceramic substrate is transparent and colorless, or transparent and colored. Both sides of the glass or glass ceramic substrate may be smooth, or there may be protrusions on one side, preferably on the side facing away from the user during operational use. Examples of transparent and colorless glass or glass ceramic substrates require good visibility through the glass or glass ceramic substrate and thus also through the cover panel, for example in observation windows, especially in observation windows for high temperature applications. It is preferable if However, it may also be advantageous to select a transparent and colorless glass or glass ceramic substrate and provide a reducing transparency coating on one side thereof, at least on one side, preferably on the side facing away from the user or operator during operational use. have. Such a configuration is possible, in particular in the application of the cover panel as a cooking panel, if the cooking appliance comprises an integrated display and/or other indicator element arranged under the cover panel or hot plate. This option provides particularly good visibility for such display elements, especially since light from the display elements will not be absorbed by the transparent colored substrate.

However, it may also be advantageous to have a transparent colored glass or glass ceramic substrate that is not particularly used only as a cooking surface. In fact, in this case, the components and/or structures arranged behind or under the cover panel will no longer be clearly visible. Thus, it may also be possible to tune the transmittance of visible light through selective color absorption of a glass or glass ceramic substrate such that certain components or structures are visible through the cover panel but not otherwise.

In the context of the present disclosure, a transparent colored embodiment of a glass or glass ceramic substrate is understood to mean that the glass or glass ceramic substrate has been dyed, in particular by means of colored metal ions. This is also referred to as volumetric coloring in the context of this disclosure. Materials and/or articles, such as, for example, glass or glass ceramic substrates, are referred to as transparent in the context of this disclosure if they do not have a scattering effect. The opposite of a transparent design is, in particular, an opaque or translucent design, where the opacity or translucency occurs due to scattering particles of the material or article. Thus, within the scope of the present disclosure, it is particularly possible for a material and/or article to cause absorption but still be referred to as being transparent, since in this case the transmittance of visible light will decrease, but visible light will scatter in this design. because it won't happen.

According to a further embodiment of the cover panel, the coating is disposed on the major surface of the glass or glass ceramic substrate facing the user during operative use of the cover panel, thus forming the top surface or the front surface. This is particularly useful if the coating is designed to be hard and/or abrasion resistant, ie particularly scratch and/or abrasion resistant. In fact, the coating is precisely the side facing the user in operational use, and is generally the side that receives the greatest surface stress of the cover panel, ie the upper surface of, for example, a cooking panel.

The top or front surface of the cover panel will generally have a special design. First, the top or front surface of the cover panel is generally smooth, while the bottom or back surface of the cover panel may have a design with, for example, protrusions. Furthermore, if the cover panel is provided in the form of a cooking surface, the upper surface of the cover panel will generally be further covered with an additional coating that marks a functional area, for example a cooking zone. Finally, the upper surface of the cover panel is also the surface on which the strength of the cover panel is determined. This means that the mechanical resistance of the cover panel to the breaking load is determined by making the individual load-bearing side, for example, the side on which the steel ball falls in a ball drop test, upward.

Another aspect of the present disclosure relates to a method for producing a cover panel according to the aforementioned embodiment comprising a physical coating process (or physical vapor deposition (PVD)). This way,

- providing a glass or glass ceramic substrate;

- introducing a glass or glass ceramic substrate into the coating chamber;

- providing a ceramic or metallic target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof and B is preferably Al; Fe, Cr, V or a mixture comprising a step,

- providing a gas, preferably oxygen, as a reactive gas;

-adjusting the pressure in the coating chamber, wherein the pressure is 1*10 ^-3 mbar or more and 5*10 ^-2 mbar or less,

- adjusting the temperature in the coating chamber above 40 °C, wherein the production temperature is preferably below 350 °C;

- performing the coating by vapor phase deposition or sputter deposition, wherein sputter deposition may be performed as DC sputter deposition or pulse sputter deposition, for example, intermediate frequency sputter deposition or high frequency sputter deposition,

- optionally by further process steps in the form of heat treatment in a furnace, preferably in a ceramization furnace, by laser exposure, by flash lamp treatment, by UV post-treatment, plasma, for example in vacuum post-treatment of the coating by further exposure by means of an oxygen plasma or plasmaline (PlasmaLine ^{® ) under atmospheric conditions, or by flame exposure and/or}

optionally adding additional substances in the form of Si or Ti with an additional substance content of less than 10%, preferably less than 5% and most preferably less than 2%.

wherein at least one major surface is at least partially coated with a coating comprising or formed mainly or substantially or entirely of a mixed oxide of the _{formula A x} B _y O _{4 ,}

The molar ratio of A to B is 0.3 or more and 0.7 or less,

the mixed oxide and/or coating is at least partially crystalline, in particular polycrystalline,

A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof,

B preferably comprises Al, Fe, Cr, V or mixtures thereof,

The coating preferably exhibits a light transmittance of greater than 70%.

Although the coating process may be carried out in-line, it is also possible that the coating is carried out as a batch process and therefore not carried out in-line.

As already explained above with respect to layer stress, the method according to an embodiment of the present disclosure, in particular by means of a coating process using the sputter deposition technique according to the embodiment, will surprisingly provide a very advantageous construction of the coating. make it possible Surprisingly, the method, in particular a sputter deposition technique, for example a pulsed sputter deposition, preferably in particular a pulsed intermediate frequency sputter deposition or a high frequency sputter deposition, is at least partially crystalline, in particular polycrystalline (or at least partly crystalline , especially with mixed oxides that are polycrystalline) have been found to make it possible to obtain coatings which nevertheless exhibit low layer stresses. This effect can be enhanced by further post-treatment of the coating, either directly under vacuum or under atmospheric conditions. Another option to promote this effect is to add at least one additional substance effective as a kind of nucleating agent.

The coated sample can be post-treated directly in the coating chamber or further processed after the coating process. This may be achieved in different ways as follows.

There is a thermal after-treatment at a temperature of at least about 400° C., preferably at least about 500° C. or higher, even more advantageously at least about 600° C. or even at least about 900° C., the maximum temperature being, in particular, preferably at atmospheric pressure. The maximum operating temperature of the cover plate or cover panel of up to 1100° C. for a period of at least 2 hours, more preferably at least about 4 hours or even longer, most preferably up to about 6 hours and possibly longer, but not exceeding 100 hours. am. In this way, the coating may be annealed, and may also be referred to or understood as being cured or, more generally, thermally post-treated or heat treated. For example, this post-treatment may be performed during the thermal strengthening process of the cover panel (especially if the cover panel comprises a glass substrate) or during the ceramization process of the cover panel (especially if the cover panel comprises a glass ceramic substrate). may be achieved. The thermal post-treatment has the particular advantage that such a thermal post-treatment can be achieved during the treatment of the cover panel after the coating step has been completed and anyway during the intended process step, for example during thermal strengthening or during the ceramization process. This means that a separate heat treatment of the cover panel is not required, but rather a thermal post treatment can be performed in other process steps. Thus, advantageously, the heat treatment can be carried out in a ceramization furnace, ie during the conversion of green glass to glass ceramic, or in a tempering furnace, ie during thermal strengthening of the glass substrate.

at most about 10 mbar, preferably at most about 5 mbar for a period of at least 5 minutes, preferably at least 15 minutes, most preferably at least about 60 minutes, but preferably up to about 10 hours, more preferably up to about 5 hours , most preferably plasma treatment (eg argon, oxygen, ammonia or hydrogen plasma) at a pressure of about 1 mbar or less, but preferably at least 0.001 mbar.

^{at least 8 J/cm 2} , preferably at least 20 J/cm ² , and most preferably at least 40 J/cm ² for at least 1 discharge, better at least 5 times, most preferably at least 10 discharges treatment with xenon flash lamps at different energies or energy densities of

Characteristic lines of the line spectrum at atmospheric pressure at least 2 hours, preferably at least 4 hours, most preferably at least about 6 hours but not more than 100 hours in a UV lamp, for example preferably 185 nm and/or 254 nm There is a treatment using a line spectrum UV lamp with

There is laser treatment.

Crystal growth can be stimulated and/or promoted by the addition of so-called nucleating agents, at least in the case of _{the A x} B _y O ₄ form comprising silicon or titanium or a mixture of these two materials. Accordingly, nucleating agents or additives may be added as an alternative to or in addition to the post-treatment step. Although the amount of additive is kept low enough not to adversely affect the physicochemical properties of the coating, it causes a decrease in the crystallization temperature. For this reason, according to one embodiment, the amount of nucleating agent is less than 10%, preferably less than 5% and most preferably less than 2% _{of A x} B _y O _{4 .} Here, the above percentages are based on atomic or mole fractions or molar amounts (also referred to as at% or mol%). In other words, z will be much smaller than the numbers x and y _{of compound A x} B _y O _{4 .} Here, C preferably comprises, or consists of, titanium or silicon element or a mixture of these two elements, or a titanium element or silicon element or a mixture of these elements.

Additional nucleating agents may be incorporated into components A and B of the alloy target, such that all three elements A, B, and C will be provided to the target with a significantly lower proportion of component C relative to A or B. As mentioned above, component C may also be defined as titanium or silicon or a mixture of these elements. This alloy target composed of or comprising three components can be treated almost identically to a two-component target due to the small amount of component C. Another possibility is to add a third component C to the plasma by a process known as co-sputtering, in which case one target material consists or may consist of components A and B and a second target material, component C. . In this case, the amount of atoms or ions of component C provided will be much less than the number of atoms or ions provided by the alloy target comprising components A and B.

Thus, according to one embodiment, the present disclosure also

- providing a glass or glass ceramic substrate;

- introducing a glass or glass ceramic substrate into the coating chamber;

- providing a ceramic or metallic target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof and B is preferably Al; Fe, Cr, V or a mixture thereof,

- providing a gas, preferably oxygen, as a reactive gas;

-adjusting the pressure in the coating chamber, wherein the pressure is 1*10 ^-3 mbar or more and 5*10 ^-2 mbar or less,

- adjusting the temperature in the coating chamber above 40 °C, wherein the production temperature is preferably below 350 °C;

- performing the coating by vapor phase deposition or sputter deposition, wherein sputter deposition can be performed as DC sputter deposition or pulse sputter deposition, for example, intermediate frequency sputter deposition or high frequency sputter deposition

wherein at least one major surface is at least partially coated with a coating comprising or formed mainly or substantially or entirely of a mixed oxide of the _{formula A x} B _y O _{4 ,}

The molar ratio of A to B is 0.3 or more and 0.7 or less,

the mixed oxide and/or coating is at least partially crystalline, in particular polycrystalline,

A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof,

B preferably comprises Al, Fe, Cr, V or mixtures thereof,

The coating preferably exhibits a light transmittance of greater than 70%,

By means of a further process step in the form of heat treatment in a furnace, preferably in a ceramization furnace or an intensification furnace, by laser exposure, by flash lamp treatment, by UV post treatment, by further plasma, for example in vacuum post-treatment of the coating by exposure to oxygen plasma or atmospheric plasmalines (PlasmaLine ^{® ) and/or by flame exposure;}

The content of additional components is less than 10%, preferably less than 5%, and most preferably based on mole fraction, to obtain a coating comprising compound A _x B _y C _z O _{4 (z is significantly less than x and y)} is less than 2% titanium or silicon or the addition of additional components comprising or consisting of a mixture of these two elements

It relates to a cover panel further comprising at least one of the following features, preferably to a method of manufacturing a cover panel according to any one of the embodiments described in the present disclosure.

Thus, according to this embodiment, it is possible for the coating to include a nucleating agent. Due to the small mole fraction of component C of the coating, _{doped mixed oxides of the formula A x} B _y O ₄ are obtained, and due to the small mole fraction of the dopant, the essential properties of the mixed oxide are still the main components A and B, for example, It is determined by the crystal structure. In the context of the present disclosure, _{a mixed oxide of the formula A x} B _y O ₄ is also a doped mixture of the _{formula A x} B _y C _z O ₄ , provided that the content of component C is 10% or less on a mole fraction basis and possibly even less It is understood to include oxides. The mole fraction may also be given in terms of the indices x, y and z, and the mole fraction MF is calculated according to the following equation.

As already mentioned above, in the cover panel obtained by the method according to an embodiment, the absolute value of the layer stress of the coating according to the embodiment is preferably at most 800 Mpa, more preferably at most 500 MPa, and most preferably 300 MPa or less. In other words, the layer stress is preferably ±800 Mpa, more preferably at most ±500 MPa, and most preferably ±300 MPa or less.

Also surprisingly, the coating or the mixed oxide constituting the coating is at least partially crystalline, in particular when the mixed oxide exhibits a spinel structure or an inverse spinel structure or an olivine structure. The formation of such a crystal structure usually requires high temperatures, for example, when preparing powders (see, for example, Alhaji et al., Optical Materials 98 (2019), section 2.2 at least 1400° C.) Temperatures are given, or Orlinski et al., Journal of the European Ceramic Society 39 (2019), section 2 mentions a temperature of 1000 °C), in which case it is known that there is an advantage in eutectic systems or single crystal formation (e.g. See, for example, Takebuchi et al., Radiation Physics and Chemistry 177 (2020), section 2, mentioning in particular a temperature of 1400° C.).

Surprisingly, with the method according to the present application, at least partial crystallinity can already be achieved at low temperatures in the sputter deposition chamber of up to 350° C., otherwise these low temperatures are usually only used for drying the precursor material ( Orlinsky et al.).

Accordingly, the present disclosure also relates to a cover panel, in particular a cover panel according to the above-described embodiment produced or producible by a method according to an embodiment of the present disclosure, and a use thereof.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the drawings in which like reference numerals denote like or equivalent features.
1 to 3 show different embodiments of a cover panel.

1 is a schematic cross-sectional view of a cover panel 1, not shown to scale, of a first embodiment of a cover panel 1 according to the present application. The cover panel 1 comprises a glass or glass ceramic substrate 10 having a first major surface 11 and a second major surface 12 and one of the major surfaces 11 , 12 , ie in this case the major surface ( 12) a coating 2 disposed thereon. The coating 2 is disposed on the cover panel 1 or on at least one area 100 of the glass or glass ceramic substrate 10 .

The coating (2) comprises a mixed oxide of the formula A _x B _y O _4, or exceeds mainly, that is, 50% by weight of a mixed oxide of the formula A _x B _y O _4, or a substantially, i.e., 90% by weight is formed in excess of, or entirely. The molar ratio of A to B is 0.3 or more and 0.7 or less. The molar ratio may in particular be 0.5. The mixed oxide and/or coating 2 is at least partially crystalline, in particular polycrystalline. A is preferably Fe, Mg, Be, Zn, Co, Si, Mn or a mixture thereof. B is preferably Al, Fe, Cr, V or a mixture thereof. The coating 2 preferably exhibits a light transmittance of greater than 70%.

Here, the region 100 is designed such that only the coating 2 and the glass or glass ceramic substrate 10 are included in this region 100 . In other words, the region 100 delimits a portion 101 , in which only the coating 2 is disposed on one major surface, in this case the major surface 12 . This part 101 of the region 100 is also shown to scale, not to scale, in FIG. 2 , which is a schematic cross-sectional view, not drawn to scale, of a further embodiment of the cover panel 1 , as an example. have. 2 also shows an additional coating 3 on the major surface 12 of the glass or glass ceramic substrate 10 .

The cover panel 1 is preferably an area in which only the coating 2 is disposed on one major surface 11 , 12 , ie in this case the major surface 12 of the glass or glass ceramic substrate 10 . It is designed to exhibit a light transmittance of greater than 70% in at least portion 101 of 100 .

However, more generally, and not limited to the exemplary embodiment of the cover panel 1 illustrated herein, the additional coating 3 may, in particular, also be applied to the major surface of the glass or glass ceramic substrate 10 in the region 100 . It is also possible to arrange on (11, 12). This additional coating 3 may, for example, be disposed on the same major surface as the coating 2 , which may generally be disposed under or over the coating 2 . The further coating 3 may comprise, for example, a conductor track or a haptic coating, or else, for example a glass flux based coating or an enamel, ie an enamel coating. FIG. 2 shows that an additional coating 3 is disposed on the same major surface 12 as the coating 2 of a glass or glass ceramic substrate 10 , wherein the additional coating 3 is a major surface of the glass or glass ceramic substrate 10 . It is shown disposed between the glass or glass ceramic substrate 10 and the coating 2 in direct contact with the surface 12 . This arrangement of the coating is intended, in particular, if the coating 2 is particularly mechanically stable and/or chemically particularly inert and the coating 2 covers the further coating 3 as a top coat, thus as a whole It may be advantageous if a mechanically and/or chemically resistant surface of the cover panel 1 is obtained.

According to this embodiment, the cover panel also comprises a region 110 in which no coating is formed, but rather only a glass or glass ceramic substrate 10 is provided. This is shown, for example, in FIG. 1 .

According to a preferred embodiment, the coating 2 has a thickness of at least 0.05 μm and not more than 3 μm. Thinner coatings usually comprise, or are formed mainly or substantially or even entirely of, mechanically and/or chemically resistant materials, such as, for example, the AB ₂ O _{4 material in the present case.} However, it is not thick enough to sufficiently improve the wear resistance of the surface of the glass or glass ceramic substrate 2 . On the other hand, coatings with a thickness exceeding 3 mu m tend to crack, and moreover, it takes a long time to form such a thick coating and is no longer economically viable.

It is advantageous if the coating 2 is transparent and colorless, since in this case the coating 2 is not visually conspicuous. In the context of the present disclosure, the coating is the color position of the cover panel 1 in the portion 101 where only the coating 2 is disposed on one major surface 11 , 12 of the glass or glass ceramic substrate 10 . (E _{101 ) is the color position (E 110} ) of the cover panel in the area 110 where no coating is disposed on the glass or glass ceramic substrate 10 and less than 20, preferably less than 15, most preferably less than 10 If the value ΔE differs by less than, it is preferably said to be transparent and colorless, and the color position E ₁₁₀ in the portion 110 and the color position E 101 in the region ₁₀₁ are , most preferably determined in the L*a*b* color system, and the difference in color positions (ΔE) is calculated using the following equation.

The color position (E ₁₁₀ ) is given by the color coordinates (a* ₁₁₀ , b* ₁₁₀ , L* ₁₁₀ ), and the color position (E ₁₀₁ ) is given by the color coordinates (a* ₁₀₁ , b* ₁₀₁ , L* ₁₀₁ ). These color positions are preferably determined in individual measurements on white tiles using, inter alia, a CM-700d spectrophotometer from Konica Minolta.

The cover panel 1 preferably has a thickness of 2 mm or less to 8 mm or less. Preferably, the thickness of the cover panel is at least 4 mm. Also preferably, the thickness of the cover panel 1 is 6 mm or less. If the cover panel 1 is made too thin, the mechanical strength will not be sufficient in terms of fracture behavior. In particular, the impact resistance and/or flexural strength a may not be sufficient for use as, for example, viewing windows for cooking panels or, in particular, viewing windows for high temperature applications. However, if the cover panel 1 is too thick, the panel becomes too heavy. Also, there may be cases where, for example, the transmission characteristics in the IR range and/or the visible light range become too poor. If, for example, a cover panel used as a viewing window in an oven or fireplace is too thick, the transfer of heat radiation to, for example, a room to be heated will not be sufficient. For example, if the cover panel 1 is used as a cooking panel, and the cover panel 1 is too thick, it may occur that a sufficiently rapid heating to the maximum boiling point can no longer be ensured.

3 shows a further schematic cross-sectional view, not drawn to scale, of the cover panel 1 . Here, the arrangement of the coatings 2 , 3 corresponds to the arrangement in FIG. 2 . In contrast to the glass or glass ceramic substrate 10 of FIGS. 1 and 2 , in which the two major surfaces 11 , 12 are smooth, here the major surface 11 is not smooth but rather has protrusions. This design of the cover panel may be advantageous, for example, if a particularly high impact strength and/or bending strength of the cover panel 1 is required. This is because, in particular, during operation and use of the cover panel 1, the protrusion that may be provided on the main surface facing the opposite direction of the user has a strength increasing effect, since cracks can easily spread on the underside where the protrusion is formed. This is because cracks cannot break the cover panel as easily as with a smooth underside.

According to one embodiment of the cover panel 1 , the cover panel is a region of the cover panel 1 in which only the coating 2 is disposed on only one major surface 11 , 12 of the glass or glass ceramic substrate 10 ( The cover panel 1 in the portion 101 of 100) is designed to exhibit a haze of less than 5%, preferably less than 2%, and most preferably less than 1% as measured according to ASTM D 1003. This means that in parts of the glass or glass ceramic substrate 10 or of the cover panel 1 where only a coating is disposed on only one major surface 11 or 12 of the glass or glass ceramic substrate 10, the cover panel is very slightly means that only the turbidity of Therefore, the cover panel 1 is very sharp in this part 101 , thus causing only slight light scattering. This is advantageous for achieving particularly good visibility through the cover panel 1 .

If the cover panel (1) or the coating (2) is designed to have a hardness of between 6 Gpa and 11 GPa as determined by a measurement method conforming to or based on DIN EN ISO 14577-1 and -4 (also known as Martens hardness), It is also advantageous. This makes it possible for the coating 2 to be particularly effective, for example, as a wear-resistant coating for protecting the surface of the cover panel from scratches, especially when applied as a top coating on the cover panel.

Moreover, according to a further embodiment of the cover panel 1 , the coating 2 covers the major surfaces 11 , 12 of the glass or glass-ceramic substrate 10 substantially over the entire surface area, ie at least of the major surfaces. The cover panel is designed to cover 90%, preferably even at least 95% of the major surface. This is particularly advantageous if the coating 2 is formed to be very hard and/or very wear-resistant, since in this case the area covered with the coating 2 over substantially the entire surface area is particularly abrasion-resistant, for example in particular This is because it exhibits scratch resistance and/or abrasion resistance.

According to a further embodiment of the cover panel 1 , the cover panel 1 is designed to be provided with an additional coating 3 . More generally, without being limited to the embodiment of the cover panel 1 shown in the figures, the cover panel is a glass or glass ceramic substrate 10 in the form of conductor tracks or other coatings such as masks, in particular also coatings 2 . It is possible to include a number of additional coatings 3 , such as coatings disposed on the major surface of However, it is particularly possible for the coating 3 to be disposed on the same major surface as the coating 2 , ie in the present case on the major surface 12 according to FIGS. 2 and 3 . The additional coating 3 covers this main surface at least partially or only partially. In particular, if the additional coating 3 is in the form of a glass flux-based coating, in particular a colored glass flux-based coating such as, for example, an enamel coating, the coating 3 will not be applied over the entire surface area, the main surface will only partially cover For example, the coating 3 may in this case be applied as a cooking zone mark. It is also possible for the coating 3 to be applied to the main surface in the form of a grid pattern. This can be particularly advantageous if a particularly high scratch resistance or abrasion resistance is required on the main surface, since the additional coating 3 in the form of a tinted glass flux based coating will usually have a thickness of several micrometers and thus, for example For example, it may serve as a spacer between the bottom of the cookware and the major surface of the glass or glass ceramic substrate. Here, a further coating 3 is disposed between the glass or glass ceramic substrate 10 and the coating 2 . This is advantageous because in this way not only the spacer effect of the further coating 3 is maintained, but the further coating 3 is also covered by the coating 2 . In particular, if the coating 2 is scratch-resistant and/or abrasion-resistant and/or particularly hard, the further coating 3 will thus also be protected from scratches and/or abrasion by the coating 2 .

According to a further embodiment of the cover panel 1 , the glass or glass ceramic substrate 10 may be transparent and colorless or transparent and colored. In certain applications, such as viewing windows, it would be particularly advantageous if the glass or glass ceramic substrate 10 does not exhibit strong absorption, such as caused by, for example, metal ions incorporated into the glass ceramic or glass that impart color due to absorption. may be In this case, the glass or glass ceramic substrate 10 will advantageously be provided in transparent and colorless form. In other applications, for example, if it is to be intentionally made difficult to see through the glass or glass ceramic substrate 10, if the substrate is provided in a transparent and colored form, for example, the cover panel 1 is used as a cooking panel. It may be more advantageous if used.

According to a further embodiment of the cover panel 1 , the coating 2 is disposed on the main surfaces 11 , 12 facing the user during operative use of the cover panel 1 and thus forms an upper surface or a front surface. .

1: Cover panel
10: glass or glass ceramic substrate
11, 12: main surface of glass or glass-ceramic substrate
100: area of the cover panel
101: part of region 100
110: area of the cover panel without coating
2: coating
3: additional coating

Claims (14)

A cover panel (1) comprising:
a glass or glass ceramic substrate (10) having a first major surface (11) and a second major surface (12);
A coating 2 disposed on at least one of the major surfaces 11 , 12 of a glass or glass ceramic substrate 10 in at least one region 100 of the cover panel 1 .
includes,
The coating (2) is formed primarily or substantially or wholly of at least one mixture of the general formula A _x B _y O ₄ of at least one comprising a mixed oxide, or the general formula A _x B _y O ₄ oxide,
The molar ratio of A to B is 0.3 or more and 0.7 or less,
the mixed oxide and/or coating (2) is at least partially crystalline, in particular polycrystalline,
A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof,
B preferably comprises Al, Fe, Cr, V or a mixture thereof,
The coating (2) preferably exhibits a light transmittance of greater than 70%. The method of claim 1,
The cover panel, wherein the coating (2) has a thickness of not less than 0.05 μm and not more than 3 μm. 3. The method according to claim 1 or 2,
The coating (2) is transparent and colorless,
The coating 2 is preferably applied to the cover panel 1 in the part 101 in which only the coating 2 is disposed on one major surface 11 , 12 of the glass or glass ceramic substrate 10 . The color position E ₁₀₁ is less than 20, preferably less than 15, with _{the color position E 110} of the cover panel 1 in the area 110 where no coating is disposed on the glass or glass ceramic substrate 10 . , most preferably by a value (ΔE) of less than 10 is said to be transparent and colorless,
_{The color position E 110} in the part 110 and the color position E 101 in the region ₁₀₁ are most preferably determined in the L*a*b* color system, the difference in the color positions (ΔE) is the following equation

,
is calculated using
Color position (E ₁₁₀ ) is given by color coordinates (a* ₁₁₀ , b* ₁₁₀ , L* ₁₁₀ ), and color position (E ₁₀₁ ) is given by color coordinates (a* ₁₀₁ , b* ₁₀₁ , L* ₁₀₁ ) and these color positions are preferably determined from measurements on white tiles using, inter alia, a CM-700d spectrophotometer from Konica Minolta. 4. The method according to any one of claims 1 to 3,
The cover panel has a thickness of 2 mm to 8 mm, preferably 4 mm to 6 mm. 5. The method according to any one of claims 1 to 4,
In a portion 101 of a region 100 of a cover panel 1 , in which only a coating 2 is disposed on only one major surface 11 , 12 of a glass or glass-ceramic substrate 10 , said cover panel 1 ) exhibits a haze of less than 5%, preferably less than 2%, and most preferably less than 1%, as measured in accordance with ASTM D 1003. 6. The method according to any one of claims 1 to 5,
and the coating (2) has a hardness of 6 GPa to 11 GPa as determined in a measuring method conforming to or based on DIN EN ISO 14577-1 and DIN EN ISO 14577-4. 7. The method according to any one of claims 1 to 6,
and the coating (2) covers the major surfaces (11, 12) of the glass or glass-ceramic substrate (10) over substantially the entire surface area of the glass or glass-ceramic substrate (1). 8. The method according to any one of claims 1 to 7,
Additional Coatings(3)
includes,
Said further coating 3 is disposed on the same major surface 11 , 12 as the coating 2 of the glass or glass ceramic substrate 10 and at least partially or only partially covers this major surface 11 , 12 . and
and the additional coating (3) is disposed between the glass or glass ceramic substrate (10) and the coating (2). 9. The method according to any one of claims 1 to 8,
The glass or glass ceramic substrate 10 is transparent and colorless, or transparent and colored cover panel. 10. The method according to any one of claims 1 to 9,
and the coating (2) is disposed on the main surface (11, 12) facing the user during operational use of the cover panel (1), thereby forming an upper surface or a front surface. 11. A method for producing a cover panel (1), preferably a cover panel (1) according to any one of claims 1 to 10, comprising:
providing a glass or glass ceramic substrate (10);
introducing a glass or glass ceramic substrate 10 into the coating chamber;
providing a ceramic or metallic target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof, B is preferably Al; Fe, Cr, V, or a mixture thereof;
providing a gas, preferably oxygen, as a reactant gas;
adjusting the pressure in the coating chamber, wherein the pressure is 1*10 ^-3 mbar or more to 5*10 ^-2 mbar or less;
adjusting the temperature in the coating chamber above 40°C, wherein the production temperature is preferably below 350°C;
performing coating by vapor phase deposition or sputter deposition, wherein sputter deposition may be performed as DC sputter deposition or pulsed sputter deposition, for example, intermediate frequency sputter deposition or high frequency sputter deposition
including,
At least one major surface (11, 12) is at least partially coated with a coating (2) comprising or formed mainly or substantially or entirely of a mixed oxide of the _{formula A x} B _y O _{4 ,}
The molar ratio of A to B is 0.3 or more and 0.7 or less,
the mixed oxide and/or coating 2 is at least partially crystalline, in particular polycrystalline,
A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof,
B preferably comprises Al, Fe, Cr, V or a mixture thereof,
The method, wherein the coating (2) preferably exhibits a light transmittance of greater than 70%. 11. A method for producing a cover panel (1), preferably a cover panel (1) according to any one of claims 1 to 10, comprising:
providing a glass or glass ceramic substrate (10);
introducing a glass or glass ceramic substrate 10 into the coating chamber;
providing a ceramic or metallic target comprising components A and B, wherein A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof and B is preferably Al, Fe , Cr, V, or a mixture thereof;
providing a gas, preferably oxygen, as a reactant gas;
adjusting the pressure in the coating chamber, wherein the pressure is 1*10 ^-3 mbar or more to 5*10 ^-2 mbar or less;
adjusting the temperature in the coating chamber above 40°C, wherein the production temperature is preferably below 350°C;
performing the coating by vapor phase deposition or sputter deposition, wherein sputter deposition may be performed as DC sputter deposition or pulse sputter deposition, for example, intermediate frequency sputter deposition or high frequency sputter deposition
including,
At least one major surface (11, 12) is at least partially coated with a coating (2) comprising or formed mainly or substantially or entirely of a mixed oxide of the _{formula A x} B _y O _{4 ,}
The molar ratio of A to B is 0.3 or more and 0.7 or less,
the mixed oxide and/or coating (2) is at least partially crystalline, in particular polycrystalline,
A preferably comprises Fe, Mg, Be, Zn, Co, Si, Mn or mixtures thereof,
B preferably comprises Al, Fe, Cr, V or mixtures thereof,
The coating (2) preferably exhibits a light transmittance of greater than 70%,
In addition, the following characteristics, namely
Further plasma, for example by laser exposure, by flash lamp treatment, by UV post-treatment, by further process steps in the form of heat treatment in a furnace, preferably in a ceramization furnace or an intensification furnace post-treatment of the coating 2 , for example by exposure to oxygen plasma under vacuum and/or ^{to a plasmaline ® under atmospheric conditions, and/or by flame exposure;}
A further component comprising or consisting of titanium or silicon or a mixture of these two elements so as to obtain a coating comprising the compound A _x B _y C _z O _{4 (z is significantly less than x and y), wherein the content of the further component is} Addition of additional components less than 10%, preferably less than 5%, and most preferably less than 2% by mole fraction or molar amount
A method comprising at least one of A cover panel, in particular a cover panel as claimed according to claim 1 , produced or producible by a method according to claim 11 or 12 . Claims 1 to 10 or claim 1 as cooking surface, display, oven viewing window, scanner cover, optical component or optical filter, viewing window, countertop, window, sheet in the field of consumer electronics, glass packaging, watch glass, protective sheet Use of a cover panel (1) according to claim 13 and/or produced by a method according to claim 11 or 12.

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