FR3121928A1 - Plate type glass or glass-ceramic element, process for producing the same and use thereof - Google Patents

Abstract

The invention generally relates to glass or glass-ceramic elements of the plate type, more particularly to glass or glass-ceramic elements which can be used in household appliances and/or heating appliances. In particular, the invention relates to plate-like glass or glass-ceramic elements comprising a plate-like glass or glass-ceramic substrate and also a coating arranged at least in sections on at least one side of the substrate. Further aspects of the present invention relate to a process for producing such a glass or glass-ceramic element and also to the use thereof. Figure for abstract: Figure 1

Description

Plate type glass or glass-ceramic element, process for producing the same and use thereof

Field of invention

The invention generally relates to glass or glass-ceramic elements of the plate type, more particularly to glass or glass-ceramic elements which can be used in household appliances and/or heating appliances. In particular, the invention relates to plate-like glass or glass-ceramic elements comprising a plate-like glass or glass-ceramic substrate and also a coating arranged at least in sections on at least one side of the substrate. Further aspects of the present invention relate to a process for producing such a glass or glass-ceramic element and also to the use thereof.

Background of the invention

Glass or glass-ceramic elements of the plate type are used for example as masking plates or separating plates in hot applications, for example as what is commonly called a hob or as a flat or curved inspection window in ovens. Here it is necessary to have a highly targeted transmission of electromagnetic radiation through the glass or glass-ceramic element of the plate type. It may for example be necessary to allow high transmission in certain wavelength ranges, for example in the infrared range, allowing thermal radiation, for example, to pass through the glass or glass-ceramic element. with as few obstacles as possible. Alternatively, it may be necessary that the transmission is not too high. This concerns in particular the visible light region, in which it is frequently necessary to have targeted shading of the regions located behind the glass or vitroceramic element with respect to an operator or user of an appliance. For safety reasons in particular, it may be necessary here that the glass or glass-ceramic element, when an appliance equipped with such a glass or glass-ceramic element is in the off state, achieves a uniform effect, more particularly what is commonly referred to as a "neutral face" effect, and in an on state that electro-optical display elements, such as displays or indicator lights, for example, are perceptible through the element clearly and without color distortion. This can significantly improve the safety of the user of such a device, in particular.

For example, glass-ceramic plates comprising a colored body glass-ceramic are known, which appear dark, practically black in color in reflected light.

Alternatively, it is also possible for the glass or glass-ceramic element to comprise a transparent glass or glass-ceramic substrate, which for shading has a coating on a main face of the glass or glass-ceramic substrate of the plate type. For example, the German lay-open specification DE 10 2007 030 503 A1 relates to a coated glass-ceramic product in which the coating has a reflective configuration and a light-shielding effect. For this purpose, a silicon coating is applied to the glass-ceramic plate. This coating exhibits different film thicknesses in the hot and cold regions, being thicker in the hot region than in the cold. The need for this is because a thin film exhibiting sufficiently high transmission in the visible light region, allowing display elements to be easily seen through it, for example, lacks temperature stability. sufficient. On the other hand, a layer of greater film thickness, as used in the hot region according to DE 10 2007 030 503 A1, is really temperature stable, but at the same time lacks sufficient transmission in the visible light region. With these layers, the display capacity is only limited. In particular, for new designs of cooking appliances, for example, allowing fully flexible assignment of display elements on the one hand and hot regions on the other hand (which are commonly referred to as "cook where you want" appliances ), therefore the glass-ceramic plates of DE 10 2007 030 503 A1 are not suitable.

The German specification laid out for public inspection DE 10 2013 104 702 A1 also concerns a coated glass-ceramic plate. The coating on the glass-ceramic hob of DE 10 2013 104 702 A1 is a multilayer coating comprising a metal layer consisting of an alloy with chromium, iron, nickel and silicon, and also a barrier layer under the form of an oxide of an alloy with chromium, iron, nickel and silicon. These layers advantageously combine a metallic mirror impression with high temperature resistance. While these coatings can be made semi-transparent by choosing a suitable film thickness, these coatings are nevertheless not tactile and do not exhibit sufficient infrared transparency.

The reason for this is that the layers of DE 10 2013 104 702 A1 are metallic in nature and therefore conductive. As a result, the use of capacitive touch sensors for these coatings is not possible. These layers, therefore, have little or no tactile capability.

It is therefore necessary to have glass or glass-ceramic elements that give a metallic impression and combine high temperature resistance with high and flexible touch and display capacity.

Object of the invention

The object of the invention is to provide glass or glass-ceramic elements which at least partly attenuate the weaknesses of the prior art. Other aspects of the invention relate to a process for producing such glass or glass-ceramic elements, and also to their use.

The present disclosure therefore relates to a plate-like glass or glass-ceramic element comprising a plate-like glass or glass-ceramic substrate and also a coating disposed at least in regions on at least one main surface of the glass or glass-ceramic substrate. The coating includes a metallic component and a semi-metallic component and has a resistance per square greater than 1 MΩ. The glass or glass-ceramic substrate has a transparent configuration. In at least one region in which the coating is placed, the glass or glass-ceramic element has a light transmission factor, τ _vis , of between 0.5% and 10%, preferably between 0.5% and 5%.

Light transmittance in the context of this disclosure refers to the transmittance in the wavelength range 380 nm to 780 nm as calculated and defined according to DIN EN 410, for example. It may also be referred to as τ _vis . Usually it is based on standard illuminant D65.

Spectral transmittance refers to the transmittance value related to a wavelength.

A design of this type for a glass or glass-ceramic element is very advantageous in particular for applications in a household electrical and/or heating appliance.

The glass or glass-ceramic substrate itself has a transparent configuration. A transparent configuration of the glass or glass-ceramic substrate here refers more particularly to the possession by the glass or glass-ceramic substrate of a visible transmission factor τ _vis (or light transmission factor) of at least 20%, preferably d at least 40%. This figure can also be higher, for example at least 80%. Such a transmission factor can be achieved, for example, by the fact that the glass or glass-ceramic substrate is not colored and/or by limiting the fraction of absorbing constituents, for example coloring ions, in the substrate by glass or glass ceramic. The transparency of a glass or glass-ceramic substrate can also be reduced by diffusion, in addition to or as an alternative to coloring by absorption. The higher the diffusion, the lower the transparency. In the context of the present disclosure, therefore, a transparent glass or glass-ceramic substrate also refers more particularly to a glass or glass-ceramic substrate in which haze is low.

More particularly, it is possible that the glass or glass-ceramic substrate is not colored by absorption and at the same time has a low haze.

In this way, the glass or glass-ceramic substrate itself is perfectly adapted to an effective perceptibility of display elements, for example displays or indicator lights, arranged behind the glass or glass-ceramic substrate from the point of view of an observer or operator. However, a disadvantage of this, on the other hand, is that other components, which may impede the perception of, for example, safety-relevant displays, are also visible in this way. It is therefore generally advantageous to apply a coating at least regionally to the glass or glass-ceramic substrate, so that disruptive components are shaded correspondingly at least in the region in which the coating is arranged. The coating, according to embodiments, may therefore also be referred to or understood as a light-shielding coating.

The glass or glass-ceramic element may therefore include, for example, omissions or masked regions which remain free of the coating.

According to embodiments, however, this is not absolutely necessary for the glass or glass-ceramic element. In the case of known plate-type glass or glass-ceramic elements which have a shadowing or light-shielding coating, it is frequently necessary to omit certain regions of the coating, since these light-shielding coatings cause a shadowing almost total, and thus the display elements and/or indicator lights are no longer visible through the coating. As a result, in these masked regions, other coatings may then need to be applied which exhibit a semi-transparent configuration. The production of such glass or glass-ceramic elements therefore encompasses various coating steps with different coating agents or materials, such as the application of specific semi-transparent screen-printing pastes in the regions omitted by the light-shielding coating, and is correspondingly expensive and complicated.

With the coating according to embodiments, this is not necessary, since the coating is configured such that the glass or glass-ceramic element, at least in a region in which the coating is disposed, has a factor of light transmission, τ _vis , comprised between 0.5% and 10%, preferably between 0.5% and 5%, preferably on the basis of a glass or vitroceramic substrate thickness of 4 mm. It is a light transmission factor which allows sufficient shading and at the same time guarantees that the display elements can be perceived easily by an observer or user of a device equipped with such a glass or vitroceramic element, such as a household appliance and/or heating appliance. At the same time, as a result, a very uniform appearance of the glass or glass-ceramic element is also possible, particularly in the off state of a household and/or heating appliance, since omissions and/or the application of other coatings, which would disturb a uniform homogeneous impression given by the glass or glass-ceramic element, are no longer absolutely necessary.

In one embodiment, therefore, the coating is applied over substantially the entire surface area of at least one major face of the glass or glass-ceramic substrate. This means more particularly that the coating covers at least 90%, preferably at least 95%, of the at least one main face. More particularly, the coating can also cover 100% of the at least one main face. According to one embodiment, therefore, the glass or vitroceramic element receives in an extremely simple way a very advantageous configuration, combining a very uniform appearance, aesthetically attractive, with better safety for the operator. This very uniform, visually homogeneous appearance is also referred to as the "neutral face", and the resulting very uniform, visually homogeneous appearance is also referred to as the "neutral face effect".

Another reason why this is possible, more particularly, is because the coating in general, without being limited to a degree of coverage of the at least one major face, is configured such that it has a greater resistance per square. at 1 MΩ. In this way, in fact, the conductivity of the coating is low enough to allow the use of capacitive touch sensors as well. In other words, this coating design is an important prerequisite for the coating to have a tactile design.

For the functionality of capacitive touch sensors, thus including a design of the coating as a tactile coating, there are two guiding criteria. First, two adjacent individual keys may not have capacitive shorting, and thus can still be read separately. This is important not only for individual keys arranged next to each other with different switch functions behind them, but also for slide switches (sliders) constructed from individual keys. A capacitive short circuit can be caused by a capacitively or electrochemically coupled electrically conductive layer spanning the two switch faces (sensor faces) of the individual keys.

Second, an individual switch must not exhibit too strong a disruptive ground signal, which is caused by capacitive coupling of grounded environments, called stray capacitances. This negative effect can be enhanced if an electrically conductive layer is capacitively coupled to the switch face of an individual key. As a result, the effective switching area of the individual key is increased, and that key couples to an increased extent to grounded environments (e.g. ambient air). This can lead to permanent triggering of the individual button, which means that it is no longer available for the switching function. Both deleterious effects can be avoided with the help of electroconductive layers, at least for interfaces with typical capacitive operation, if the sheet resistance of the layer is greater than 1 MΩ, preferably greater than 5 MΩ, more preferably really greater than 10 MΩ or more.

The higher the resistance per square, the closer the individual keys can be arranged adjacent to each other. At the same time, operational safety is improved at higher sheet resistances. At higher resistances per sheet, the coupling to stray capacitances is weaker, resulting in more sensitive sensing and a lower likelihood of incorrectly detected sensor inputs.

Tailoring of coating properties in particular regions is not necessary. More particularly, it is not necessary to adapt the layer thickness of the coating in certain regions of the glass or glass-ceramic element so as to obtain special "display regions" or "sensor region". Instead, with a design of the glass or glass-ceramic region according to the present disclosure, it is simply amazingly possible to apply a uniform coating which also works in applications where a flexible arrangement of hot regions, display and sensor elements, such as “cook anywhere” appliances, are present.

Suitable sensors include, for example, touch sensors already referred to (capacitive touch sensors or keys). In addition, sensors are frequently mounted under or behind masking plates of household appliances and/or heating appliances, such as cooking appliances, for example. The coating must therefore also be transparent with respect to these sensors, these sensors usually emitting in the near infrared region. These sensors are usually sensors used for training and communication, such as communication with a hood in the case of cooking appliances, for example, or temperature sensors.

The following definitions apply in the context of this disclosure:

Plate-like article or product generally means that the article or product has a shape in which the lateral dimension in a first spatial direction of a Cartesian coordinate system is at most one-fifth of the lateral dimensions in the other two spatial directions, perpendicular to the first spatial direction, of the Cartesian coordinate system. In other words, the thickness of an article of the plate type (or of a window or plate or strip) is at most one-fifth of its length and width. An article of the plate type, for example an element of the plate type, can be plane, that is to say flat, or even curved, for example such as a curved or curved window. In addition, it is generally possible that the plate or window also has cutouts or recesses, for example for passages of mechanical rotary controls or for access passages, for example of gas burners for hoods, more particularly in the case where the plate-like article or the plate-like element or the plate would be used as a heating plate. In the context of this disclosure, the concepts of window and plate are used synonymously. More specifically, a plate-like design can also refer to a window-like design.

In addition, it is also generally possible that the plate-like article or the plate-like element is designed such that the side on which the coating is arranged is smooth, but it is also generally possible that this side has a size configuration. This may in particular be the case, for example, when the element of the plate type is intended to be adapted or used as a cooking plate and comprises, for example, a glass-ceramic or is formed from a glass-ceramic. The design with a thickened side on which the coating is arranged is, however, not limited to a plate-like element which is suitable and/or intended for use as a hob, but may also appear in the context of other elements of the plate type for different purposes or determinations.

A substrate refers to an uncoated article. An element includes a substrate and a coating. An element can also be understood as a coated substrate, in which case, correspondingly, a substrate can also be understood as an uncoated element.

References in the context of this disclosure to a thickness of the glass or glass-ceramic element are generally to the thickness of the glass or glass-ceramic substrate. This is because the coatings which are deposited on the glass or glass-ceramic substrate to give a glass or glass-ceramic element are very thin, being at most in the range of a few micrometers or less, and thus within the limits of precision measuring the thickness of the element corresponds to the thickness of the substrate.

The main faces of a plate-type article, such as an element or substrate, are currently understood to be the faces which together represent more than 50% of the total surface area of the article. They may also be referred to as sides – in particular, depending on the precise spatial arrangement, front side or back side of a window or plate, or top side or bottom side of it. No main face is therefore a side face, for example like the edge faces of a window or a plate-like article or product. The main faces can more particularly be arranged parallel to each other. A parallel arrangement more specifically refers to one in which the normals to the major faces together enclose an angle of at most 5°.

A metallic configuration for a coating is understood herein to mean that the coating comprises nonmetals only to a limited degree, the nonmetal content of the coating being more particularly less than 4% by weight. A metallic configuration therefore contrasts with a non-metallic configuration, in which the coating comprises at least 4% by weight, preferably more than 4% by weight, more particularly more than 10% by weight of non-metals. A non-metallic configuration may more particularly be understood as, or be referred to as, a ceramic or part-ceramic configuration, in which case, for example, the coating material may have an oxide and/or nitride configuration.

A semi-metal (also called a metalloid) in the context of this specification refers to an element which on the basis of its properties falls between those of a metal and those of a non-metal. The group of semi-metals in the context of this specification includes the following: boron, silicon, germanium, arsenic, antimony, bismuth, selenium, tellurium, polonium. A semi-metallic component is a component comprising a semi-metal. The semi-metallic component more particularly comprises silicon and/or germanium.

A tactile coating more particularly means that the coating has a sufficiently high sheet resistance greater than 1 MΩ.

According to one embodiment, the coating has a reflective configuration. In other words, the coating is designed in such a way that it reflects electromagnetic radiation in the visible light range, i.e. in the range from 380 nm to 780 nm. According to one embodiment, the coating can have a mirror effect, that is to say can produce a metallic appearance. A reflective configuration of this type can particularly advantageously contribute to a very uniform overall impression given by the glass or glass-ceramic element, and this can be important particularly for safety reasons. The reason for this is that, in this way, any deviation from a normal state of a household and/or heating appliance provided with such a glass or vitroceramic element, for example, can be perceived very easily, by a visual display that flashes in an interrupt scenario, for example, since this display is visually quite prominent in the overall uniform appearance of the item.

The reflective properties of a coating, such as a coating according to the embodiments, for example, generally depend on the precise design of the surface to which the coating is applied in each case. Thus, the reflectance will generally be higher if the surface of the substrate is very smooth. Here, for example, a coating is also understood to be reflective within the meaning of the present disclosure if, applied to a substrate having a smooth surface, it exhibits the following reflection properties: an average reflection in the visible spectral range is to say from 380 nm to 780 nm, between 10% and 30%, reached more particularly for a coating according to embodiments which is configured as a single layer, or between 20% and 70%, reached in particular for a coating according to embodiments which is configured as a multilayer system, more particularly comprising three layers. These values are reached more particularly for embodiments in which the substrate has a smooth configuration, that is to say does not have structures which are for example without thickness or are not rendered rough. A substrate surface is also understood more particularly as being smooth if it is obtained by rolling with an unstructured roll. An unstructured or smooth substrate surface may in particular also refer to a substrate surface having a roughness, more particularly a roughness R _a , of less than 1 μm.

For structured substrate surfaces, lower reflection values or reflection factors are achieved, which in the visible spectral range are between 2% and 20% for directed measurement and for a roughness R _a between 1 µm and 5 µm.

In other words, according to this embodiment, the glass or glass-ceramic element can be designed such that the coating has a reflective configuration. Reflected in this context refers to a coating, or a coating is referred to as reflective, when the glass or glass-ceramic element in the at least one region exhibits the following reflective properties:

- an average reflection in the visible spectral range, that is to say from 380 nm to 780 nm, of between 10% and 30%, achieved more particularly for a coating according to embodiments which is configured as a single layer , Where

- an average reflection in the visible spectral range, that is to say from 380 nm to 780 nm, of between 20% and 70%, achieved more particularly for a coating which is configured as a system of layers, more particularly comprising at least three partial coats,

in which more particularly these values indicated above are reached when the glass or vitroceramic element has a smooth configuration on the main face or the side on which the coating is arranged, "smooth" referring more particularly to a main face or a side, for example the upper side or lower side of a plate obtained by rolling with an unstructured roll, and/or to a main face (or a side, such as an upper side or lower side) having a roughness, more particularly a roughness R _a , less than 1 μm,

or in which the main face or the side on which the coating is arranged has a roughness of between 1 µm and 5 µm and is preferably structured and the glass or glass-ceramic element in the region has an average reflection in the visible spectral range, i.e. between 380 nm and 780 nm, between at least 2% and at most 20%, or

a gloss, preferably determined with the Rhopoint Qs gloss meter, of at least 87 GU, preferably at least 100 GU, more particularly according to a measuring angle of 20°, of at least 93 GU, preferably at least 100 GU , more preferably at a measuring angle of 60°, and at least 97 GU more particularly preferably at a measuring angle of 85°, wherein the main face or the side on which the coating is placed has a roughness, more particularly a roughness R _a , of between 1 µm and 5 µm and is preferably structured,

Where

a gloss, preferably determined with the Rhopoint Qs gloss meter, of at least 500 GU, preferably at least 700 GU, more particularly according to a measuring angle of 20°, of at least 200 GU, preferably at least 250 GU , more preferably at least 270 GU and very preferably at least 300 GU, more particularly preferably according to a measurement angle of 60°, and at least 99 GU more particularly preferably according to a measurement angle of 85°, in which more particularly these values indicated above are achieved when the glass or vitroceramic element has a smooth configuration on the main face or the side on which the coating is arranged, "smooth" also referring more particularly to a main face or a side, for example the upper side or a lower side of a plate, which is obtained by rolling with an unstructured roll, and/or a main face (or a side, such as an upper side laughing or lower side) having a roughness, more particularly a roughness R _a , of less than 1 μm.

An average reflection refers to the arithmetic mean of the reflection values in a range of wavelengths.

Unless otherwise specified, within the scope of this disclosure, a reflection measurement is made on the side of the element facing the user, i.e., the user side or top side or the visible side of the plate-shaped element. This means that the measurement values obtained during reflection or reflectance measurements relate to the visible face or the user side of the element. That is, the measurement is always made through the substrate, i.e., through the glass or glass-ceramic material, since the coating is arranged on the back side/bottom side/ below the element, that is, facing away from the user under operating conditions.

Gloss is reported here in GU gloss units. With an instrument as indicated above, in particular, gloss measurements according to the relevant international standards are possible.

The brightness values obtained depend, for example, on the presence or not of a structuring in the region. Illustrative measurement values are listed in the table below:

sample # measured directly on the support black undercoat angle measuring 20° 60° 85° 1 88.05 94.31 97.30 2 100.13 101.14 97.97 Comparative example 1 84.40 91.01 97.44 3 770.41 341.32 100.51 4 763.52 340.43 99.87 5 529.45 275.64 100.11 Comparative example 2 105.67 140.95 104.40

For the measurement the samples were placed in each case on a black underlayer. The measurement was made through the glass or vitroceramic element.

Sample 1 here is a glass element in which the coating is a four-layer coating comprising a layer of silicon nitride and in which the main face is structured in the region of the coating – i.e. in the measurement region. The visual impression given by the coating when viewed through the glass substrate is silver-gray.

Sample 2 here is also a glass element in which the coating is a two-layer coating comprising a layer of silicon nitride and in which the main face is structured in the region of the coating – i.e. in the region of measurement. Again, the visual impression given by the coating when viewed through the glass substrate is silver-grey.

Comparative example 1 or reference 1 relates to the measurement of a substrate or a glass element which does not include a coating but is structured in the measurement region.

Samples 3 to 5 are each glass-ceramic elements in which the main face or side was in each case unstructured, i.e. was smooth, in the region of the coating – i.e. say in the measurement region.

Sample 3 is a four-layer coating comprising SiO₂ ; the visual impression given by this coating when viewed from above, i.e. through the glass ceramic, is silver.

Sample 4 is a four layer coating including a layer of silicon nitride, which similarly gives a silvery impression when viewed through the glass ceramic.

Finally, sample 5 is a two-layer coating comprising a layer of silicon nitride; again, the visual impression given when viewed through the glass ceramic is silver.

Comparative Example or Reference 2 is an uncoated glass-ceramic substrate.

The visual impression when the coating itself is observed may very well deviate from this impression; in the case of samples 1, 2, 4 and 5, the coatings show a golden configuration when observed directly.

From the measurement values it is evident that as a result of the coating, the gloss in the at least one region of the substrate or element is increased compared to an uncoated substrate, especially at viewing angles 20° and 60°. This is particularly marked for the case of a smooth surface in the at least one region, as can be perceived, illustratively, from samples 3 to 5.

The division of gloss grades into different angles here is as follows:

20 degrees: 0-2000 GU (where 0 is completely dull and 2000 is a perfect mirror)

60 degrees: 0-1000 GU (where 0 is completely dull and 1000 is a perfect mirror)

85 degrees: 0-199 GU (where 0 is completely dull and 199 is a perfect mirror).

In other words, it is evident from the above measurement values that particularly in the case of a smooth substrate main face, very high mirror effect surfaces are obtained in the at least one region. In this region, therefore, the coating exhibits an almost metallic mirror-like configuration or exhibits a so-called "metallic appearance", with sufficient opacity, a color perceived preferably as neutral upon reflection ( also frequently referred to as "silver") and generally a high reflectance.

However, in the case of a structured configuration of the main face, a metallic appearance is obtained in the at least one region in which the coating is arranged, this appearance being similar to the impression given by stainless steel surfaces such as those obtained with control panels or other areas, such as stainless steel masking elements, for example. With such a structuring, it is more particularly possible to evoke the impression of a brushed metallic surface, such as brushed stainless steel.

Such elements can therefore be particularly preferable in order to achieve a uniform appearance of a working environment, since in this way, for example, masking plates are obtained which, in optical terms, are not considerably striking. or different from other metal surfaces.

This is shown for illustrative purposes by the photographic image on the drawings. The representation in question here is the photographic representation of a glass element. Observation here is through the glass substrate. The coating has an omission, which in this case is a dark area in the lower right region of the photographic image. The patterning here is applied to achieve a zebra running from right to left, which stands out as local differences in coating brightness in the photographic representation. Nevertheless, the general metallic character of the visual appearance is clearly evident.

Surprisingly, therefore, in accordance with the present disclosure, masking plates can be obtained which simultaneously exhibit reflective and tactile configurations. Consequently, these masking plates give a metallic effect, without the metallic properties of coatings which are disadvantageous for the applications discussed here, and particularly the high conductivity, being present.

According to one embodiment, the glass or vitroceramic element, at least in the region in which the coating is arranged, has a color locus in the CIEL*a*b* system with L* greater than 55 and with a* , b* in the range of -12 to +12, preferably -10 to +10, more preferably -5 to +5. The color locus is preferably determined or can be determined in a color locus measurement with a color locus instrument, the coating being disposed on the major side of the glass or glass-ceramic substrate facing away from the instrument for color locus. If there should be another coating on the side of the element opposite the coated side, it can be removed before the measurement, by polishing or laser ablation, for example, in order to allow a measurement to which the coating is placed on the main face of the glass or glass-ceramic substrate facing away from the instrument for color locus. Such a polishing step in particular generally has no influence, or at most a negligible influence, on the result of the measurement of the color locus of the coating. Preferably, L* is greater than 60, more preferably greater than 62. In the context of this specification, generally, color values or color locus are or are preferably determined in a measurement against a black trap, in particular preferably with a Konika-Minolta CM-700d spectrophotometer.

According to this embodiment, then, the coating is configured as a reflective coating exhibiting a neutral color locus upon transmission. A neutral color locus during transmission is particularly advantageous since in this way display elements and/or indicator elements can be seen through the coating with as little color distortion as possible. A neutral color locus during a transmission may already be present, for example, when the colorimetric values a*, b* are in a range in each case from -30 to +30. For a coating configured as a single layer, for example, a value of 108 for a* and 22.4 for b* can be achieved, or for a coating constructed as a system of layers (more particularly a system of layers comprising at minus three partial layers), an a* value of 46 and a b* value of 8.1. A neutral color locus during transmission is possible with these colorimetric values a*, b*.

Depending on the precise design of the coating and/or element, therefore, it is possible to establish a color perceived as vivid. For example, values of L* which may even be well above 55 or 60, or even 62, may be obtained.

According to one embodiment, the coating has a thickness of less than 1000 nm, for example less than 500 nm or even less than 200 nm. Higher coating thicknesses are unfavorable, since at higher film thicknesses there may be cracks or delamination effects of the coatings. Also for manufacturing reasons, it may be preferable to choose very low thicknesses, since in a physical vapor deposition process, for example, a thinner coating can be deposited in less time than a thicker coating. Moreover, at very large coating thicknesses (or film thicknesses) greater than 1000 nm, the resulting transmission values may be unfavorable, that is to say too low.

A certain minimum thickness of the coating preferably at least 20 nm, however, may be advantageous in order to guarantee the shadowing effect of the coating. This minimum film thickness is preferably 20 nm, but this value can also be different depending on the precise composition of the coating. For example, coatings with a purely metallic configuration can produce sufficient shading even at lower film thicknesses than some coatings with a non-metallic (or ceramic) configuration.

A particular advantage of the glass or glass-ceramic element is that the coating is suitable not only for what is commonly referred to as a hot range but also for what is commonly referred to as a cold range or display range. The thickness of the coating need not be established specifically depending on whether the corresponding range of the glass or glass-ceramic element is intended to be used as a hot range or as a cold range or a display range. According to one embodiment, therefore, in particular, the coating has a constant thickness.

A constant thickness means here that the thickness of the coating, in the at least one region of the glass or glass-ceramic element in which the coating is arranged, fluctuates by at most 40%, preferably by at most 20%, more preferably at most 10%, most preferably at most 5%, based on the average thickness of the coating in this region. This average thickness is defined as the average between the greatest thickness of the coating and the least thickness of the coating.

The coating is also particularly advantageous in that the coating on the one hand has a tactile design and on the other hand, at the same time, can also have a reflective configuration. In one embodiment, therefore, the overlay is designed such that it simultaneously exhibits a tactile and reflective configuration. In particular, according to this embodiment, the coating can be configured such that it has a color locus in the CIEL*a*b* system with an L* value greater than 55, preferably greater than 60 and greater preferably greater than 62, or even more. With the coating according to this embodiment, in particular, a vivid design with a mirror reflection is possible, the glass or glass-ceramic element being at the same time tactile in the region in which the coating is arranged.

A design of this type for a coating or for a glass or glass-ceramic element of the plate type, having reflection values and/or colorimetric values, more particularly L* values, such as coatings or glass or glass-ceramic elements of the plate type according to embodiments, while at the same time still being tactile, was hitherto not possible. Until now, in fact, high reflection values of the type obtained for an unstructured substrate or an unstructured substrate surface were usually only possible through pure metallic coatings, which, however, are conductive and by therefore non-touch in their configuration.

According to one embodiment of the coating, the coating is designed such that the coating or at least a part of the coating, such as an underlayer or partial layer, particularly in the case of the coating configured not as a single layer but rather as a layer system, comprising three layers, for example, exhibits an absorption coefficient k greater than 0.1 at a wavelength of 550 nm. High values of k are advantageous, and k for example can be greater than 1, for example can be about 2 or even can be greater than 2. The refractive index n at 550 nm can be greater than 2, for example example. For a coating of metallic configuration, for example, it is advantageous that n at 550 nm is less than 2 and k is greater than 2. According to an embodiment of a non-metallic or (partly) ceramic coating, it can be advantageous that n at 550 nm is greater than 2 and k is greater than 0.1 but less than 3. The reason for this is that in these cases an absorbent coating can advantageously be obtained which at the same time has a high sheet resistance, giving thus a glass or vitroceramic element which, in the at least one region in which the coating is arranged, has an adjustable light transmission factor of between 0.5% and 5%.

According to another embodiment, the coating comprises less than 10% by weight, preferably less than 5% by weight and more preferably less than 2% by weight of hydrogen. This is advantageous because hydrogen generally decreases the thermal resistance of the coating. The hydrogen content of the coating should therefore be limited, and, as indicated, is preferably less than 10% by weight. Preferably, therefore, no deliberate hydrogen doping takes place.

Another aspect of the present disclosure also relates to a process for producing a glass or glass-ceramic element, preferably a glass or glass-ceramic element according to an embodiment of the present disclosure. The process includes the steps of

- supply of a glass or glass-ceramic substrate of the plate type having a transparent configuration,

- introduction of the glass or glass-ceramic substrate into a coating chamber,

- supply of a target comprising at least one semi-metallic component and/or at least one metallic component in the coating chamber,

- establishment of a pressure in the coating chamber, in which the pressure is between at least 5*10 ^-4 mbar and at most 5*10 ^-2 mbar,

- sputter coating, in which the sputtering can take place as direct current sputtering or as alternating current sputtering, for example as medium-frequency or high-frequency sputtering,

to give a glass or glass-ceramic element of the plate type comprising a glass or glass-ceramic substrate of the plate type and also a coating arranged at least in regions on at least one main face of the glass or glass-ceramic substrate,

wherein the coating comprises a metallic component and a semi-metallic component and has a sheet resistance greater than 1 MΩ, and wherein the glass or glass-ceramic element, at least in a region in which the coating is disposed, has a light transmittance, τ _vis , of between 0.5% and 10%, preferably between 0.5% and 5%, preferably based on a glass or glass-ceramic substrate thickness of 4 mm.

It is generally possible that the glass or glass-ceramic substrate already comprises, before the process is implemented, at least one coating, that is to say, for example, has a coating on an upper side or on an upper side. lower, in the form of what is commonly referred to as a cooking zone marking, for example. However, it is also alternatively possible for another coating or, where appropriate, two or more other coatings to be applied only after the sputtering.

According to the process at least one target is provided in the coating chamber. It is possible, for example, that a single target is provided, which then comprises at least one semi-metallic component and at least one metallic component. It is also possible, however, that a target is provided which includes a semi-metallic component, and another target which includes a metallic component. This is the case, for example, with so-called cathodic co-sputtering.

A coating according to one embodiment, configured for example as a metallic component comprising only aluminum and silicon apart from unavoidable impurities, can be produced, for example, during a co-sputtering process. In this case, a first magnetron is provided with a pure aluminum target, and a second magnetron with a silicon target – for technical reasons, in order to facilitate sputtering, this target can also comprise a certain amount of aluminium, in the form of an aluminum stabilization of up to 20% by weight, for example. The two targets are arranged relative to each other such that the main orientation of the sputtering lobes together opens out onto one plane of the substrate. In this plane, the established composition of the resulting coating should conform to the selected operating parameters, yet shifts in the direction of aluminum or in the direction of silicon on the plane of the substrate. The sputtering operation is performed such that the sputtering power on the aluminum target is approximately twice as large as the power on the silicon target.

By adding a reactive gas, it is possible to obtain compositions which have a higher aluminum content than coatings of metallic configuration, for example. In this case, for example, it is also possible to obtain compositions with a 1:1 ratio (based on weight) of aluminum to silicon. Too high a fraction of aluminum in a coating can have a deleterious effect on the thermal and/or chemical resistance of the coating, due to the stabilizing properties of silicon. A particular challenge when producing (partially) ceramic coatings is that of establishing and also monitoring the correct operating point. This concerns in particular the establishment of the correct partial pressure of reactive gas. The operating point to be established here is one that is located in the metallic region of what is commonly referred to as the S-curve of reactive sputtering. This point can be stably established and maintained not only through reactive gas regulation but also through the use of a part-ceramic target, in which case there must be an amount of residual gas defined in the installation. The objective of this specific operating point is the establishment of an absorptive, non-stoichiometric coating whose metallic properties are preserved as much as possible, in terms of optical impression, but which nevertheless has a very high resistance per sheet. Coatings of this type can, for example, also be described as having an absorption coefficient k of at least 0.1 or more at a wavelength of 550 nm and/or a refractive index of 2 or more. at a wavelength of 550 nm.

In addition, the present disclosure also relates to a glass or glass-ceramic element, more particularly a glass or glass-ceramic element according to embodiments of the disclosure, which is produced or at least can be produced during a process according to the present disclosure. .

Yet another aspect of the present disclosure also relates to the use of a glass or glass-ceramic element, more particularly of a glass or glass-ceramic element according to embodiments and/or produced or at least capable of being produced during a process according to embodiments of the disclosure, such as, for example, a masking plate for a household and/or heating appliance, more particularly as a masking plate for a cooker, in particular for a gas or stove induction, or as an oven window, or as a fireplace sight glass, or as an inspection window in a refrigerator, or as an inspection window in a microwave appliance, or as a front glass of an operating element , more particularly of an operating element of a coffee machine or in an oven, or as a worktop in a kitchen or laboratory unit, such as, for example, a drying oven or a table , or in a consumer electronic device, for example in a smartphone.

Description of the drawings

The invention is explained in more detail below with drawings.

The , in a diagrammatic representation not to scale, shows a side view of a glass or vitroceramic element 1 according to one embodiment. The glass or glass-ceramic element 1 comprises a glass or glass-ceramic substrate 10, which in this case has a configuration of the flat plate type. As a general rule, without being limited to the example shown in the of a glass or glass-ceramic element 1 or of a flat plate-like glass or glass-ceramic substrate 10, the element 1 or substrate 10, respectively, can also have a curved or bent configuration.

The glass or glass-ceramic substrate 10 of the plate type comprises two main faces 11, 12. These main faces 11, 12 can also be generally referred to as sides 11, 12, depending in particular on the precise spatial arrangement of the substrate 10, upper sides and bottom or front and back sides, for example. Since the sides 11, 12 of the substrate 10 and the coated substrate or element 1 correspond to each other, it should be recognized that, as a general rule, the statements made concerning the main faces or sides 11, 12 of the substrate 10 are also correspondingly valid for the sides or main faces of element 1.

In general, the side which during the operational use of an appliance, for example a household electrical appliance and/or heating appliance equipped with such a substrate 10 or element 1, is located the highest or the furthest front, is referred to as top side or front side, respectively.

The glass or glass-ceramic substrate 10 may be referred to, for example, as a glass substrate. In this case, the glass substrate may comprise soda-lime glass, aluminosilicate glass or borosilicate glass and may more particularly be referred to as soda-lime glass window or borosilicate glass window. Soda-lime glasses are advantageous because they can be produced and processed inexpensively. The substrate 10 can more particularly take the form of a tempered soda-lime glass window, preferably heat-tempered. This is advantageous since in this way the mechanical strength of the substrate 10 is improved. For some designs of a glass substrate 10, however, it may be preferred that the substrate 10 comprise borosilicate glass, configured, for example, as a borosilicate glass window. The reason for this is that, compared to soda-lime glasses, borosilicate glasses show improved chemical resistance and can also inherently show improved thermal resistance, meaning that such borosilicate glass windows do not even necessarily need to be soaked. However, also for windows made of borosilicate glass, hardening, for example thermal hardening, is also not excluded. For the placement of a glass substrate 10 in a domestic appliance and/or heating appliance with high service temperatures of up to 500°C, for example, such as for an inspection window in a pyrolysis, therefore, it may be advantageous to design the glass substrate 10 as a borosilicate glass window or as a chemically toughened glass window, including, for example, an aluminum silicate glass or an aluminum silicate glass. aluminum and lithium.

According to one embodiment, the glass or glass-ceramic substrate 10 takes the form of a glass-ceramic substrate. In this case, the glass-ceramic is preferably of a transparent configuration, in other words has not received any black coloring by absorption, and at the same time is preferably clear, thus showing only minimal diffusion. A glass-ceramic substrate 10 of this type - and a glass-ceramic element 1 correspondingly - can be used with particular advantage in applications involving exposure to particular functional loads, particularly high thermomechanical stresses, for example such as what is commonly referred to as a hob in the case of cooking appliances, especially in combination with gas burners or induction coils for heat generation.

As can be perceived from the schematic side view of the , not to scale, the coating 2 is arranged at least by regions on at least one of the main faces 11, 12 of the glass or vitroceramic substrate 10, and is presently arranged in fact on the main face 12, which is configured here like the bottom side. In other words, therefore, the glass or glass-ceramic element 1 has the region 101 in which the glass or glass-ceramic substrate 10 and the coating 2 are arranged. Coating 2 can generally be understood as and/or be considered as a light-shielding coating, or as a coating 2 with a light-shielding or shading effect.

The regional arrangement of the coating 2 on at least one side 11, 12 of the glass or glass-ceramic substrate 10 is now further explained in the , a plan view of a glass or vitroceramic element 1. The coating 2 here, as also on the , is disposed on the underside of the glass or glass-ceramic substrate 10. As indicated, the glass or glass-ceramic substrate 10 is configured such that it has a light transmittance of at least 20%, preferably of at least 40%, preferably at least 80%, preferably based on a glass or glass-ceramic substrate thickness between 3 mm and 4.5 mm, particularly preferably 4 mm, and so the coating 2 is also perceptible to an observer through the glass or glass-ceramic substrate 10. The glass or glass-ceramic element 1 therefore comprises here the region 101, in which the coating 2 is placed, and also the region 100, which is free of coating 2. In the illustrative representation of the , the region 100 is configured in the marginal region of the glass or glass-ceramic substrate 10 or, correspondingly, of the glass or glass-ceramic element 1, and specifically passing around the coating 2. In general, without being limited to the representation 1 and 2, it is possible for the coating to be applied over substantially the entire surface area of the glass or glass-ceramic substrate 10. A coating applied over substantially the entire surface refers to a coating which covers at least 90%, preferably at least 95%, of the at least one main face. More particularly, the coating 2 can also cover 100% of the at least one main face 11 or 12.

In general, without being limited to the embodiments shown in Figures 1 and 2 of a glass or glass-ceramic element 1, the glass or glass-ceramic element 1 or the glass or glass-ceramic substrate 10 can have a thickness between 0 0.03 mm and 10 mm or more, preferably between 0.03 mm and 6 mm, more particularly between 0.7 mm and 5 mm, very preferably between 3 mm and 5 mm. For example, substrate 10 can be configured as a thin glass or thin glass-ceramic substrate with a thickness in the range of 0.03 mm to up to 1 mm, or as a thick glass or glass-ceramic substrate having a thickness between 1 mm and 10 mm or even more.

The light transmittance of the element 1 in the at least one region 101 is preferably determined generally, without being limited to the illustrative representation of the element 1 on the , for a substrate thickness between 3.0 mm and 4.5 mm, particularly preferably 4 mm. The light transmittance of elements 1 having different substrate and/or element thicknesses can be compared with each other to establish whether they are within the scope of the protection.

For example, thicker elements 1 and/or substrates 10 can be thinned down to a thickness of 4 mm.

Thinner elements 1 and/or substrates 10 can be brought to a thickness of 4 mm by stacking, and possible thinning if necessary, to allow a physical measurement of the transmission and a corresponding determination of the light transmission factor also, in order to determine if these thinner substrates 10 and/or elements 1 are within the scope of the protection.

It should be kept in mind here that the purpose of thinning and/or stacking is only to adapt the thickness of the substrate, i.e. the thickness of the glass material or glass-ceramic, and so any thinning or stacking must not change the thickness of the coating 2.

A design of the coating 2 with a high degree of coverage of at least 90% or more or at least 95% or more or even 100% is particularly advantageous since in this way it is possible to omit costly and complicated structuring operations , with the aim, for example, of integrating inspection windows under which display elements or operating elements can be arranged. Such a coating 2, for example, can therefore also be produced in a physical vapor deposition process, such as a sputtering process, for example, in a very simple way. Nor is it necessary for the coating 2 to be configured with different thicknesses in different regions of the glass or glass-ceramic element 1. Instead, according to the embodiment as present schematically and not to scale on the , it is possible for the coating 2 to have a constant thickness. This means that the thickness of Coating 2 fluctuates by at most 40%, based on the maximum thickness of Coating 2 in region 101.

These highly advantageous designs of the glass or glass-ceramic element 1 are possible by virtue of the fact that the glass or glass-ceramic element 1 is designed generally, without being limited to the illustratively represented and described embodiments of the glass or glass-ceramic 1 in Figures 1 and 2, such that the coating 2 comprises a metallic component and a semi-metallic component and also has a sheet resistance greater than 1 MΩ, and the glass or glass-ceramic element, at less in the region 101 in which the coating 2 is arranged, has a light transmission factor of between 0.5% and 5%, preferably based on a thickness of the glass or vitroceramic substrate 10 of 4 mm. According to embodiments, the sheet resistance can be greater than 5 MΩ or even greater than 10 MΩ, and very high sheet resistances in the GΩ range are also possible. Preferably, however, the resistance per square is limited and is no more than 25 GΩ, more preferably no more than 10 GΩ, very preferably no more than 1 GΩ, and most preferably no more than 100 MΩ.

As a metallic component, the coating can typically include aluminum, titanium, molybdenum, magnesium, silver, or zinc. The coating preferably comprises aluminum, titanium, magnesium, molybdenum, silver or zinc, more preferably aluminum, silver, magnesium or zinc, more preferably aluminum. These metals are preferred because they are highly reflective metals which result in a high reflectance also in compounds or in alloys. The semi-metallic components of coating 2 can be silicon or germanium, preferably silicon.

Preference is given to a configuration of the glass or glass-ceramic element 1 in which the coating, as shown illustratively in the , is disposed on the bottom side of the glass or glass-ceramic substrate 10 (present side 12). The reason for this is that in this way the really thin coating 2, which according to one embodiment has a thickness of less than 1000 nm, is protected against mechanical attack. This is advantageous, for example, particularly in applications of the glass or glass-ceramic element 1 as what is commonly referred to as a cooking surface. The reason for this is that in this case the upper side of the glass or glass-ceramic element 1 is subject to increased mechanical attack due to contact, for example, with cookware. In this way, the very thin coating 2 could be at least partly worn and consequently lose its shading effect. Coating 2 is preferably even thinner than 1000 nm, for example having a thickness of less than 500 nm. Even lower film thicknesses are possible, 200 nm or even less, for example, and they may also be preferable, since very thin layers of this type may imply shorter operating times during production and at the same time, depending on the precise design of the coating, can also allow low light transmittances of, for example, only 0.5%, or high light transmittances of, for example, 5%, in the region 101. Accordingly it is possible, particularly at high light transmittances, to advantageously use very high resolution display elements, examples being high resolution displays, under coatings 2 really very thin designed accordingly. Advantageously, however, the coating should be at least 20 nm thick.

According to one embodiment, the coating 2 is designed such that it has an absorption coefficient k greater than 0.1 at a wavelength of 550 nm. Large values for k are advantageous, and k, for example, can be greater than 1, can be about 2, for example, or can even be greater than 2. The refractive index n at 550 nm can be greater to 2, for example. In the case, for example, of a coating 2 configured in metallic fashion, it is advantageous for n at 550 nm to be less than 2 and for k to be greater than 2. According to one embodiment of a coating 2 that is non-metallic or (partly) ceramic, it can be advantageous that n at 550 nm is greater than 2 and that k is greater than 0.1 but less than 3. In these cases, in fact, advantageously, an absorbent coating 2 can be obtained which at the same time has a high square resistance, and thus a glass or glass-ceramic element 1 is obtained which, in the at least one region 101 in which the coating 2 is arranged, has an adjustable light transmission factor of between 0 .5% and 5%.

According to another embodiment, the coating 2 has a reflective configuration, more particularly a mirror. In other words, according to this embodiment, the coating 2 can be configured as a reflective coating, more particularly highly reflective, with a metallic appearance.

According to another embodiment, the glass or vitroceramic element 1, at least in the region 101 in which the coating 2 is arranged, has a color locus in the CIEL*a*b* system in which L* has a value greater than 55 and a* and b* are each situated in the range between -12 and +12, preferably between -10 and +10 and more preferably between -5 and +5. The value of L* may for example be 60 or more, more particularly even 62 or more. The color locus can preferably be determined during a color locus measurement with a color locus instrument, the coating 2 being disposed on the main face of the glass or glass-ceramic substrate 10 which faces away from the instrument. for color locus. In other words, the measurement of the color locus preferably takes place through the glass or glass-ceramic element 1, and thus, in the embodiment of the element 1 which is shown illustratively in the , the instrument for color locus is arranged on the main face 11. The measurement is made during a reflection against a black well.

According to an advantageous embodiment, the coating 2 has a tactile and reflective configuration at the same time. In particular the coating 2, according to this embodiment, can be designed such that the coating 2 has a mirror reflection and at the same time is tactile. In this way, it is possible to combine a metallic appearance with a tactile capability. This was not possible in this way until now. Until now, for example, mirror coatings were only possible with metallic materials as described in DE 10 2013 104 702 A1. However, they were not tactile, because the metallic material according to DE 10 2013 104 702 A1 is conductive and therefore has too low resistance per square for the use of what is commonly called capacitive touch screens.

According to another embodiment, coating 2 comprises less than 10% by weight, preferably less than 5% by weight and more preferably less than 2% by weight of hydrogen. This is advantageous because hydrogen generally decreases the thermal resistance of Coating 2. The hydrogen content of Coating 2 should therefore be limited, and, as indicated, is preferably less than 10% by weight.

The coating 2 according to one embodiment may have a metallic configuration. A metallic configuration generally means that the non-metal content of the coating is limited and is preferably less than 4% by weight in total. The quantity of the elements oxygen O and/or nitrogen N in the coating 2 is preferably in total less than 4% by weight, more preferably in each case less than 2% by weight.

In general, without being limited to the embodiments described above, the coating may have, for example, a composition A _x B _y , in which A is at least one metal having a high reflection, such as aluminum, titanium, molybdenum, magnesium, silver or zinc, for example preferably aluminium, titanium, magnesium, molybdenum, silver or zinc, more preferably aluminium, silver, magnesium or zinc, better still aluminum, and B is at least one semi-metal, such as silicon or germanium, for example.

According to this embodiment, the coating 2 preferably comprises silicon Si as a semi-metallic component (or semi-metallic component). The metallic component or the metal is or preferably comprises aluminum Al. Very preferably, according to this embodiment, the coating has a silicon content greater than 70% by weight and an Al content less than 30% by weight. , based on the total amount of metallic and semi-metallic components in the coating.

The coating 2 can for example be configured as an AlSi-based coating. Above a silicon content of at least about 70% by weight and preferably up to 99% by weight (based in each case on the total weight of metallic and semi-metallic components), such coatings have a resistance per square greater than 1 MΩ, which allows the majority of touch sensors used on the market to operate. The semi-conductive properties or the semi-metallic properties of silicon are advantageous in this context, to establish a high sheet resistance, and thus the coating 2 has a very high electrical insulation configuration. For various reasons, however, pure silicon coatings are not useful. A first reason is that a sufficiently high luminosity during reflection cannot be obtained in this way, and secondly, such systems, during a process such as sputtering, for example, can be produced with disadvantages of operation such as severe arcing, due to the semiconductor properties or semi-metallic properties of silicon. At present, therefore, it is advantageous to set the aluminum fraction as high as possible. This can be achieved, for example, by providing a sputtering target comprising aluminum and silicon. It came out surprisingly that it is possible, despite the high aluminum content of up to almost 30% by weight, for example, in such targets and, correspondingly, in the resulting coatings, to obtain any likewise sufficiently high resistances per square. The assumption was that, as in DE 10 2007 030 503 A1, for example, an aluminum fraction should be minimized or possibly avoided, by boron doping of the silicon target, for example.

According to another embodiment, the coating 2 has a non-metallic configuration. A non-metallic configuration can also be understood as a (partly) ceramic or ceramic configuration of the coating. A non-metallic or (partially) ceramic configuration of a coating or material is assumed here for a coating that includes non-metals at not less than 4% by weight. In the case of a non-metallic configuration of the coating 2, the semi-metallic component is or preferably comprises silicon, and the metallic component of aluminium. In a particularly preferred manner, the coating comprises the elements oxygen and/or nitrogen, and in the case of additions of nitrogen, for example, the nitrogen content of coating 2 is preferably greater than 4% by weight, and/or in in the case of oxygen additions, for example, the oxygen content of the coating is preferably greater than 10% by weight. According to a particularly preferred variant of a coating 2 configured in a non-metallic manner, the silicon content of coating 2 is greater than 40% by weight and the aluminum content of coating 2 is less than 60% by weight.

In both cases it is possible that there are residues of the respective other gas in the layer. This appears due to entrainment of these gases via the substrates and/or via the transport vector. The fractions of the respective other gas, however, are usually in a region of less than 4 wt%, preferably less than 2 wt%, based on coating 2.

A non-metallic configuration of this type for the coating 2 can be achieved, for example, by means during production, during a magnetron sputtering operation, for example, of an additional reactive gas – for example, oxygen O ₂ or nitrogen N ₂ as reactive gas. In this way, a nitride or oxide or generally oxynitride compound of general formula A _w B _x O _y N _z is formed. Here too, A is at least one metal having a high reflection, such as aluminium, titanium, molybdenum, magnesium, silver or zinc, for example, preferably aluminium, titanium, magnesium , molybdenum, silver or zinc, more preferably aluminium, silver, magnesium or zinc, more preferably aluminium, and B is at least one semi-metal, such as silicon or germanium , for example. The amount of nitrogen N or oxygen O or the total amounts of oxygen O and nitrogen N in these coating materials, on a weight basis, is, however, always less than the total amounts of the components A and/or B. The coating can be configured, for example, as an aluminum silicon nitride AlSiN _x or aluminum silicon oxide AlSiO _y or, generally, as an aluminum silicon oxynitride AlSi _z O _y N _x , in which case the precise amount of aluminum and silicon in the coatings may in each case be variable. In particular, it is not only intended that the coating 2 comprises aluminum and silicon in equal fractions, either on the basis of the weight or the quantity of substance. Instead, generally, depending on a precise design, the coating 2 can comprise more aluminum than silicon or vice versa, whether it is configured as a nitride or as an oxide or as an oxynitride. Consequently, it may be advantageous to increase the aluminum content of coating 2 in order to achieve a very high reflectance. As a variant, the tactile capacity of coating 2 can advantageously be improved by increasing the fraction of silicon in coating 2.

According to one embodiment, the operation takes place so as to form a sub-stoichiometric oxide, nitride or oxynitride. It is particularly advantageous here to have a substoichiometric nitride system. The reason for this is that due to the addition of a certain amount of nitrogen, the aluminum and silicon are incorporated more firmly into the microstructure of the coating, and thus the risk of degradation of the coating under the effect of heat load is reduced. In particular, in this way, the sheet resistance (or conductivity) remains within the specified limits even under the effect of or after a thermal load.

A sub-stoichiometric compound, for example an oxide, nitride or oxynitride, refers here to the non-metal or non-metals having been added in deficit with respect to the component or components metallic (s) and / or semi-metallic ( s), so that the metallic component or components and/or semi-metallic component(s) are not completely oxidized and/or the atoms of one or more components are not all present or must not all be present with the same oxidation number.

Substoichiometric oxide, nitride or oxynitride means in particular here that the nitrogen N content of a nitride or oxygen O content of an oxide, or the sum of the oxygen O and nitrogen N content of an oxynitride, is always less than the fraction of semi-metallic component and/or metallic component in coating 2, based in each case on weight fraction.

In the case of a 1:1 weight-based ratio for silicon to aluminum in Coating 2, configured as a Coating 2 Nitride or as a Coating 2 at least primarily Nitride, beyond with a nitrogen content of 5% by weight of nitrogen in the coating 2, a sufficiently high resistance per square of at least 1 MΩ, preferably at least 5 MΩ and more preferably at least 10 MΩ, has been reached. The composition of the coating 2 here can preferably be determined by means of energy dispersive spectroscopy at an accelerating voltage of 5 keV, in which preferably two or more measurements, for example five measurements, are carried out and the average of the measurement points obtained is reported. The residual oxygen content in Liner 2 was approximately 1% by weight, this figure depending on the respective state of the installation and therefore being difficult to establish and define with precision. A nitride or nitrided or at least predominantly nitride (or predominantly nitrided) configured coating 2 is therefore understood in the context of the present disclosure to be a coating 2 produced with oxygen present only in the context of inevitable traces. When the coating 2 has been obtained during a physical vapor deposition process, such as sputtering, this process is, for example, one in which oxygen has not been added as a reactive gas and/or no (partly) ceramic oxide target was used. Unavoidable traces of oxygen are in this case, as observed above, different, governed by the production process, and generally do not amount to more than 4% by weight.

In the case of a coating 2 configured with an oxide, sufficiently high resistances per sheet can be achieved through a minimum oxygen content greater than 10% by weight, depending on the precise ratio of aluminum to silicon in coating 2. With nitride or mostly nitride coatings as well, a different limiting nitrogen and/or oxygen content may be sufficient or necessary to achieve sufficient sheet strengths, through the ratio of aluminum to silicon in coating 2.

Both with a metallic configuration of the coating 2 and with the non-metallic or (partly) ceramic configuration of the coating 2 it is presently possible to realize the advantageous properties of the glass or glass-ceramic element 1. More particularly, it is possible with the latter to provide a glass or vitroceramic element 1 which at least in regions has a coating 2 on at least one main face (or side) 11, 12, and which, at least in the region 101 which has the coating 2 , has a light transmittance of between 0.5% and 5%, preferably based on a glass or glass-ceramic element 1 thickness of 4 mm, and wherein the coating has a resistance per square greater than 1 MΩ, preferably greater than 5 MΩ, more preferably, in fact, greater than or equal to 10 MΩ.

The is a schematic perspective view, not to scale, of a glass or glass-ceramic element 1 according to one embodiment, in which here the glass or glass-ceramic element 1 is arranged so that the coating 2 is turned to the top. Generally, however, without being limited to the illustrative embodiment, it may be advantageous for the coating to be provided on the main face (or the side) of the glass or glass-ceramic element 1 or of the glass or glass-ceramic substrate 10 which during of an operation is configured as the lower side or rear side of the glass or glass-ceramic element 1. The reason for this is that in this way the coating 2 is protected by the substrate 10 against mechanical attacks resulting, by example, the movement of the cookware on the upper side of a glass or glass-ceramic element 1 used as a hob. The coating 2 here is applied over the entire surface area of a main face or side of the glass or glass-ceramic substrate 10.

According to one embodiment as shown schematically and not to scale on the , the glass or glass-ceramic element 1 may comprise another coating 3. This other coating 3 is arranged on the at least one main face 11, 12, presently on the main face 12, at least in regions between the glass substrate or glass-ceramic 10 and coating 2. In the schematic representation of the , the main face 12 of the glass or glass-ceramic element 1 or of the glass or glass-ceramic substrate 10 faces downwards, and thus is configured as the lower side. The other coating 3 is placed on the main face 12, in the present case directly on the substrate 10, and in addition in the region 101 of the glass or vitroceramic element 1 in which the coating 2 is placed. Here, however, there is no complete overlap between the other coating 3 and the coating 2. Generally, however, without being limited to the embodiment shown in the , it is possible that the other coating 3 and the coating 2 are arranged with a complete overlap, in other words that the other coating 3 is arranged throughout the region 101 as well, and particularly between the at least one main face (presently the main face or the side 12) of the substrate 10 and the coating 2. Omissions in one of the coatings, for example the coating 2 or another coating 3, can be implemented or obtained by means of masking, for example, more particularly by what is commonly referred to as masking plates. This concerns in particular the case of a coating which is obtained by a physical or chemical vapor deposition process. It is also possible, however, that an omission is obtained, for example, by a printing process, possibly, for example, in the case of the coating, such as another coating 3 implemented in the form of a layer of pigmented enamel. This is because a printing process allows lateral structuring of a coating in the form of omitted regions and directly coated regions during the application process. If this other coating 3 is arranged on the at least one main face 11, it can function, for example, as a decoration on the upper side, on the basis in particular of a pigmented enamel, or as a scratch-resistant layer, on the in particular a layer of Al _x Si _y N _z having been subjected to sputtering, or a combination of the two.

Depending on the nature and precise design of the other coating 3, it can perform different functions. It is also possible that two other coatings 3 or more are placed between the substrate 10 and the coating 2.

For example, the other coating 3 can be designed as a single layer comprising or composed of SiO ₂ or generally composed of silicon oxide. A single layer of this type can lead to an increase in the mirror effect, and thus the L* value can be further increased in this way. Advantageously in this case, the other coating 3 is designed in such a way that the coating 2 and it completely overlap, that is to say that the other coating 3 is also arranged in the entire region of the glass or glass-ceramic element 1 which carries the other coating 2. In this way it is also possible, if desired, to modify the color locus of the glass or glass-ceramic element 1. In particular it is even possible in this way way to even out or compensate for a possible color tint of the glass or glass-ceramic substrate 10. iron content, resulting, for technical reasons, from impurities in the batch. This yellow dye can be compensated by another coating 3 designated as color matching layer. In particular, it is generally also possible for the other coating 3 to be designed as a layer system, for example as an optical layer system comprising multiple layers of material. However, for economic reasons, it may be advantageous for the coating 3 to be configured as a single layer.

Alternatively or additionally, another coating 3 can be designed in such a way that it prevents the diffusion of elements from the glass or glass-ceramic. In other words, alternatively to color matching and/or reflection enhancement, as described above, the design of the other coating 3 can be such that it acts as a diffusion barrier. . The other coating 3 can more particularly, according to one embodiment, be designed such that it acts as a diffusion barrier to the exit of alkali metals or alkali metal ions from the substrate. This can advantageously increase the lifetime of the glass or glass-ceramic substrate 10 and, correspondingly, of the glass or glass-ceramic element 1.

Alternatively or in addition to another coating 3 as described above, the glass or glass-ceramic element 1 may comprise a masking layer 4. This is illustratively shown in the schematic cross-sectional representation, not scale, of a glass or vitroceramic element 1 on the . Here, the glass or vitroceramic element 1 of the additionally comprises a masking layer 4, which is arranged at least regionally on the coating 2.

As shown schematically in the , the design of the masking layer 4 may be such that it does not completely mask the coating 2. In addition, it is also possible that the masking layer 4 and the other coating 3, as also shown schematically in the , are also applied only in partially overlapping regions of the major face (or side) of the glass or glass-ceramic substrate 10. Generally, however, without being limited to the specific embodiment shown in , it is possible that the masking layer 4 completely masks the coating 2. In addition, generally, without being limited to the specific embodiment of the , it is also possible that the other coating 3 and the masking layer 4 are also applied in completely overlapping regions. A design in which the other coating (or, if applicable, multiple other coatings) 3, coating 2 and masking layer 4 are applied over the entire area of one side (e.g. the main face 12) of the substrate 10, is more particularly also conceivable.

Here, it can be particularly advantageous for the masking layer 4 to completely cover the coating 2. Such a layer 4 can act, for example, as protection against oxidation or corrosion of the coating 2. For a ceramic configuration, but under-stoichiometric and /or nitride, of the coating 2, in particular, in the case of a metallic configuration of the coating 2 and/or generally in the context of the use of the glass or vitroceramic element 1 in cooking applications, especially those in which particularly high temperatures may occur, the configuration of the masking layer as an oxygen barrier may be particularly advantageous. Since coating 2 is configured as a semi-transparent coating, masking layer 4 can additionally also serve to slightly change or adapt the color locus of glass or glass-ceramic element 1 in region 101.

In general, the other coating 3 and/or the masking layer 4 can comprise or consist of SiO ₂ , SiO _x , SiON, SiN _x , AlO _x , TiO _x , SnO _x , MgO _x , ZnO, ZrO _x , YO _x , MoO _x , HfO _x and/or mixtures of these substances. Furthermore, as a variant or in addition, porous coatings are also conceivable and/or the other coating 3 and/or the masking layer 4 can also comprise fluorides, for example MgF ₂ .

Coating 2 preferably has a generally amorphous configuration. A configuration of the coating 2 of this type as an amorphous coating, more particularly an amorphous coating with respect to x-rays, can be particularly advantageous if the desire is to have a highly resistant coating 2. Particularly for applications in which the glass or glass-ceramic element 1 is exposed during operation at elevated temperatures, therefore, an amorphous configuration of the coating 2 of this type can be advantageous, but also for applications in which the coating is possibly exposed to a corrosive environment. In this case, an amorphous design of this type may be preferred particularly for the use of a glass or glass-ceramic element 1 in a household appliance and/or heating appliance. The reason for this is that an amorphously patterned coating of this particular type has no interfaces in the form of crystal faces along which corrosive substances can migrate into the coating 2. In this way, a Corrosion with respect to substrate 10 can be at least reduced by coating 2. According to one embodiment, coating 2 has an amorphous configuration and more particularly has a structureless and/or amorphous morphology with respect to x-rays. A structureless morphology means that Coating 2 does not include grain boundaries and/or other structures, such as growth structures, for example, but instead exhibits a homogeneous configuration. The term "amorphous" is also understood in the context of the present disclosure to refer in particular to that which is amorphous with respect to x-rays. According to one embodiment, in other words, the coating 2 thus does not have a crystalline configuration.

According to another preferred embodiment, the glass or vitroceramic element 1 has a high thermal resistance. The high thermal resistance of the glass or glass-ceramic element 1 is presently manifested, in particular, in the stability of the optical properties, more particularly in the stability of the light transmission factor and/or of the color locus, which is defined as above - below:

- after an 80 h thermal load of the glass or glass-ceramic element 1 at 390°C, the difference in light transmission factor of the glass or glass-ceramic element 1 in the region 101 after a thermal load and before a load temperature is at most 5% absolute, preferably at most 3% absolute, and/or

- after an 80 h thermal load of the glass or glass-ceramic element 1 at 390°C, the color locus difference of the glass or glass-ceramic element 1 in the region 101, ΔE, is at most 20, preferably at most 10, more preferably at most 5 and very preferably at most 2, in which ΔE is determined as follows:

,

wherein the color locus E _vT relates to the color locus of the glass or glass-ceramic element 1 in the region 101 before a thermal load and is given by the colorimetric coordinates a* _vT , b* _vT and L* _vT , and the color locus E _nT is the color locus of the glass or glass-ceramic element 1 in the region 101 after a thermal load and is given by the colorimetric coordinates a* _nT , b* _nT and L* _nT , and is preference determined in each case when measured against a black well, more particularly with a Konica-Minolta CM-700d spectrophotometer.

The difference in light transmittance of the glass or glass-ceramic element 1 in the region 101, amounting to at most 5% on an absolute basis, means presently that the light transmittance can fluctuate up to 5 points of percentage. In other words, this means that for a light transmittance of 5% in region 101 before thermal exposure, this transmittance after thermal exposure can be between 0% and 10%. Preferably, however, this difference is less than 5 percentage points and is at most 3 percentage points.

According to another embodiment, the coating 2 has a refractive index n of at least 2 or more and/or an absorption coefficient of at least 0.1 or more at a wavelength of 550 nm.

According to one embodiment, the glass or vitroceramic element 1 is configured as a glass element and, in the region 101 in which the coating 2 is arranged, has a light transmission factor of between 0.5% and 10% , preferably between 0.5% and 5%, more preferably between 0.5 and 3.5%, better still between 0.5 and 1.5%.

According to another embodiment, the glass or glass-ceramic element 1 is configured as a glass or glass-ceramic element and, in the region 101 in which the coating 2 is arranged, has a light transmission factor of between 0.5% and 10%, preferably between 0.5% and 5%, more preferably between 2% and 5%.

The , schematically and not to scale, shows another embodiment. The design of the glass or glass-ceramic element 1 here is such that like the coating 2 on at least one main face, presently the main face (or side) 12, which in this case is designated as the lower side of the substrate made of glass or glass-ceramic 10, it comprises a structuring layer 5. This structuring layer 5 can be, for example, a ceramic coating, which can be applied with a lateral structuring by means of screen printing or inkjet printing , and thus the structuring layer 5 is applied at least by regions in a region 501 of a main face, presently the main face 12.

For example, the structuring layer 5 can be applied in the form of a grid in a region 501, as shown illustratively in the . This structuring layer 5 can more particularly be a clear or only slightly diffusing, colorless coating, for example a flow-based glass coating, which can be applied by means of a printing process, such as screen printing or inkjet printing. The colorless coating can also be a sol-gel coating without pigments or dyes, which can be applied by means of ordinary coating processes, for example by means of screen printing and ink-jet printing.

However, the structuring layer 5 can also contain pigments, in particular effect pigments and/or dyes. By adding pigments and/or dyes, the reflective and optical scattering properties as well as the transmission of the coating can be influenced in a targeted manner.

In this case, contrary to what is represented schematically on the , it is also possible that the surface of the coating 2 in the region 501 is not smooth but instead has a relief corresponding to the elevations in the structuring layer 5, in other words following at least in part the elevations in the structuring layer 5. Generally, without being limited to the example shown in the of a glass or glass-ceramic element 1, it is possible for such a structuring layer 5 to be combined with one or more coatings 3 and/or with a masking layer 4. The structuring layer 5 is placed more particularly between the substrate 10 and/or on the at least one main face or side of the substrate 10 and of the coating 2, preferably directly bordering the substrate. Even when one or more other possible coatings 3 are present, the structuring layer 5 can be configured more particularly as the lowest bordering coating, directly bordering the substrate 10. The one or two other coatings 3 or more and the coating 2, and also any masking layer 4, are in this case arranged above the structuring layer 5.

It is also possible and may even be preferred that, in deviating from the not-to-scale schematic representation of the , the structuring layer 5 can be arranged on the side 11 of the glass or glass-ceramic substrate 10 opposite the coating 2. In this way, in the visual perception of an observer, a 3D effect is obtained, which is caused by the mirror effect of the structuring layer 5 on the coating 2. This effect can be advantageous, because in this way surface defects in the glass or glass-ceramic substrate 10 are concealed. Therefore, such an arrangement of the coatings on the glass or glass-ceramic substrate 10 allows particularly favorable sequences of process steps to be selected. For example, it is possible that the printing of the structuring layer 5 is first carried out, that the substrate 10 is then ceramicized and that the substrate thus converted into glass-ceramic or the substrate 10 is subjected to thermal tempering, by means of what during said thermal steps the baking of the structuring layer 5 is carried out. Finally, the coating 2 can then be applied during another step by means of sputtering.

Furthermore, it is generally also possible and may be preferred that the structuring layer 5 is present on both sides of the substrate 10, whereby, for example, the structuring layer is present on one side in a different grid than on the other side. If the structuring layer 5 is present on the lower side of the substrate 10, then other layers can also be applied on the upper side, for example decorations, cooking zone markings, stitch sequences, logos or the like.

A structuring layer 5 of this type can be advantageous particularly when the coating 2 must be prevented from having too great a mirror effect, in order, for example, for safety reasons, to prevent excessive blinding of an operator or user. an appliance fitted with the glass or glass-ceramic element 1.

Such a structuring layer 5 can also additionally have an aesthetic effect, so that, for example, the correspondingly designed glass or glass-ceramic element 1 gives the impression of a brushed stainless steel surface.

The and the , schematically and not to scale, shows an illustrative domestic appliance and/or heating appliance 60, here illustratively encompassed by a range including an oven and also a cooking appliance (also referred to as a cooktop or hob ). The cooking appliance may in particular be a gas or induction cooking appliance. A household appliance and/or heater 60 of this type generally comprises a glass or vitroceramic element 1 according to embodiments. The household electrical and/or heating appliance 60 can generally be designed, according to one embodiment, such that it further comprises at least one display and/or operating element 70 and/or one sensor 80. In the case of a cooking appliance, it can also comprise, for example, gas burners or induction coils. The appliance 60 illustrative here comprises two glass or vitroceramic elements 1 according to embodiments, particularly, on the one hand, as a masking plate in a cooking appliance, for example, and as an inspection window for an oven. The coating 2 (not designated here) is arranged in each case on the side of the glass or glass-ceramic element 1 which in the installed state faces the user or the operator of the appliance 60 - it that is to say, in the case of element 1, designated as a masking plate of a cooking appliance, on the lower side, and, in the case of element 1 designated as an inspection window, on the back side.

Is shown illustratively on the a first display element 70 in an on state, such that the display is visible through the glass or glass-ceramic element. Also shown in the lower left region of this element 1 are the operating elements 70, which can be referred to, for example, as touch regions for the operation of the device 60. In this context, it is interesting to note , however, that these operating elements 70 here are really visible and can also be identified by means of an upper side decoration, for example. The good visibility of these operating elements 70 on the , however, serves illustrative purposes in particular. In fact, an advantage of the design of the glass or vitroceramic element 1 is above all that such operating and/or display elements 70 do not specifically have to be perceptible in a disturbing way, also allowing the configuration, in particular, of a "neutral side" effect.

This is illustrated schematically and not to scale by the . In this case, display element 70 is off, and is thus hidden by element 1 and not visible, and the other display elements 70 in the lower left region of upper element 1 are also not more noticeable. In particular, it is also possible in this way to design the elements 1 in such a way that they form a visual unity with other structural elements of the apparatus 60, thus being matched to each other in terms of appearance. This is not only visually appealing but also, in addition, increases the visibility of the display elements 70 in the event of, for example, a disturbance on the apparatus 60, and thus increases operator safety.

Finally, the , schematically and not to scale, shows a design of a glass or vitroceramic element 1 on which its lower side 12 comprises a sensor 80. This element 1 can be, for example, the glass or vitroceramic element 1, designated as a masking plate, of the device 60 according to the and the , which in addition to display elements and/or operating elements 70, which for the sake of clarity are not shown here, also has a sensor 80, for example a temperature sensor.

According to one embodiment, the coating 2 has a structureless and/or amorphous morphology with respect to x-rays. A structureless morphology means that Coating 2 does not include grain boundaries and/or other structures, such as growth structures, for example, but instead exhibits a homogeneous configuration.

According to one embodiment, the element 1 has a design such that the coating 2 and the entirety of the glass or glass-ceramic element 1, more particularly in the region 101, reveal an optical transmissibility in the near infrared, allowing communication with sensors. This means that according to this embodiment, the spectral transmittance of the glass or glass-ceramic element 1, more particularly in the region 101, in a range of wavelengths comprised between 850 nm and 2500 nm, is at least 3% (or 0.03). In other words, the transmittance measured in this wavelength range, especially in the 101 region, is always greater than 3% for each wavelength.

Generally, without being limited to one of the embodiments represented in the figures, the coating 2 can take the form of a single layer or otherwise the form of a system of layers. A coating 2 is understood to be a system of layers when it comprises two or more layers. The implementation of the coating 2 as a system of layers is shown illustratively by the , in a schematic representation not to scale.

The shows another preferred embodiment of the glass or glass-ceramic element 1. According to this particular embodiment, the coating 2 takes the form of a system of layers 20. The system of layers 20 or the coating 2 can more particularly be configured as a three-layer system, thus comprising three layers or being made up of three layers.

In accordance with this particular embodiment, therefore, coating 2 may be interrupted by a dielectric layer, to produce a three-layer system comprising layers 2a, 2b and 2c. In this case the layers 2a and 2c of the coating 2 generally have a construction such that they comprise at least one metallic component and at least one semi-metallic component. The layers 2a, 2c can therefore have the general composition A _x B _y in the case of a metallic configuration or the composition AB _x O _y N _z in the case of a (partly) ceramic configuration, with A generally as metallic component and B generally as a semi-metallic component. It is more particularly possible for the layers 2a and 2c to be metallic or non-metallic or, respectively (in part) ceramic according to the embodiments configured as described above in the disclosure. In this case, the composition of layers 2a and 2c may be different or the same within the limits of usual manufacturing tolerances. More particularly, it is also possible that one of the layers 2a, 2c has a (partly) ceramic configuration and that one has a metallic configuration, or that the two layers 2a, 2c have a metallic or (partly) ceramic configuration. , but differ in their composition. Generally, however, it may be preferable for manufacturing reasons that the composition of layers 2a, 2c be the same within the manufacturing tolerance. Layer 2b (also referred to as intermediate layer) may generally comprise dielectric material and may also be referred to as dielectric layer or intermediate layer, layer 2b additionally and preferably being designed such that the refractive index n at 550 nm of layer 2b is lower than that of layers 2a, 2c, and that the absorption coefficient k of layer 2b at 550 nm is lower than the absorption coefficient k at 550 nm of layers 2a, 2c. The intermediate layer 2b can preferably comprise SiO ₂ or be composed of SiO ₂ . Due to the described layer structure of the coating 2 as a layer system 20, therefore consisting of or comprising the layers 2a, 2b and 2c, it is therefore possible, extremely advantageously, surprisingly, to to achieve increased L* values, while retaining the other properties of the coating 2, these being, more particularly, the high resistance per square and the transmission established in a targeted manner in the visible and also in the near infrared. In particular, it is possible in this way to achieve very high L* values of up to 70 or more. Additionally, there may be further subdivisions, which means that the layer system 20 may also include other layers, and therefore may be designed, for example, as a four-layer or five-layer system.

Generally, therefore, according to embodiments, the glass or glass-ceramic element 1 can have a design such that the coating 2 is configured as a system of layers 20 comprising partial layers, preferably comprising three partial layers 2a, 2b , 2c, wherein at least two partial layers 2a, 2c comprise at least one metallic component and at least one semi-metallic component. They contain at least one intermediate layer 2b. The at least one intermediate layer 2b comprises a dielectric material. Preferably, the at least one intermediate layer 2b has a refractive index n at 550 nm which is lower than that of the at least two other partial layers (2a, 2c). More preferably, the absorption coefficient k of the intermediate layer 2b at 550 nm is lower than the absorption coefficient k at 550 nm of the at least two other partial layers (2a, 2c).

A design of this type is particularly advantageous because it is possible in this way to achieve very high L* values while maintaining the resistance per square greater than 1 M ohm and the light transmission factor between 0.5% and 5 %.

It is also possible in this way, surprisingly, to achieve an extremely neutral color locus in the transmitted light. Therefore, in the case of coatings 2 configured as a single layer and comprising a high fraction of silicon, more particularly in the case of a coating 2 configured in a metallic manner, the color locus of the coating or of the glass element or glass-ceramic 1 in region 101 is frequently yellowish. This is unfavorable with regard to the integration of displays or other display elements, LEDs, for example, since there is a corresponding displacement in the color locus. Surprisingly, it appeared that this displacement of color locus could be avoided by implementing the coating 2, as described above, in the form of a system of layers 20, thus comprising a dielectric layer 2b between the layers 2a, 2c.

According to this embodiment, with the coating 2 implemented as layer system 20, it is possible in particular to achieve a* values and b* values in each case in the range between +15 and -15, in each case preferably in the range between +10 and -10.

According to a specific example of a coating 2 implemented as a system of layers 20, an a* value of 4.6 and a b* value of 8.6 could be achieved.

The layer thicknesses of layers 2a, 2b and 2c can be identical or different. They are preferably located in the region of at least 50 nm in total. In this arrangement, the individual layers 2a, 2b and 2c can go below a thickness of 20 nm. Layer 2a is preferably between 10 nm and 200 nm, layer 2b preferably between 20 nm and 300 nm and layer 2c preferably between 10 nm and 200 nm.

Finally, Figures 11 and 12, for four selected (partly) ceramic samples 6 to 9 of glass or glass-ceramic elements according to embodiments, show the refractive index n ( ) and the absorption coefficient k ( ) as a function of wavelength.

The layer composition for these four samples was in each case a weight-based ratio of aluminum to silicon. The values obtained by measuring these samples, for the resistance per square, the light transmission factor τ _vis and the colorimetric values, are collated in the two tables below, table 2 setting out the corresponding values obtained after coating and the table 3 setting out the values which were obtained after a thermal load, in this case at 390°C for 80 hours.

sample vs composition values after coating resistance per square
[ohms] _screw
[%] L* has* b* 6 AlSiO _x ( 50: 50) 1.69E+09 4.5 54.2 -2.47 -5.67 7 AlSiN _x ( 50: 50) 4.25E+08 3.32 58.86 2.89 9.39 8 AlSiN _x ( 50: 50) 6.00E+07 3.22 59.29 -2.97 4.74 9 AlSiN _x ( 50: 50) 2.00E+07 2.24 60.2 0.67 6.85

sample after thermal load resistance per square
[ohms] _screw
[%] L* has* b* ∆E 6 1.69E+09 4.5 54.2 -2.47 -5.67 11.3 7 4.25E+08 3.32 58.86 2.89 9.39 2.2 8 6.00E+07 3.22 59.29 -2.97 4.74 2.5 9 2.00E+07 2.24 60.2 0.67 6.85 2.0

Additionally, below, the film thicknesses of these samples are shown:

sample 6: 176 nm

sample 7: 117 nm

sample 8: 100 nm

sample 9: 110 nm

It turns out that samples 6-9 show good color locus stability even after temperature loading, as can be seen from the corresponding ΔE values. The general impression or profile of these coatings and, respectively, of the glass or glass-ceramic elements comprising them is completed by a low transmission in the visible range, a vivid, reflective, metallic color impression, and a low conductivity. .

Finally, the following two tables show illustrative values for glass or glass-ceramic elements according to embodiments comprising metal-patterned coatings. Again, values were reported after coating ("as deposited") and after thermal loading, again at 390°C for 80 hours.

Sample 10 here is a coating that includes 23 weight fractions of Al and 77 weight fractions of silicon. The coatings of samples 11 and 12 are coating systems and include AlSi as coating 2, as coating comprising a metallic component and a semi-metallic component, and also other coatings, which can act as a barrier, with respect to oxidation, for example.

sample vs composition values after coating resistance per square _screw
[%] L* has* b* 10 AlSi23/77 1.40E+08 2.95 61.63 -3.2 2.97 11 SiO2 ₊ AlSi ₊ SiO2 7.10E+07 3.46 62.18 -5.49 -0.47 12 SiO ₂ +AlSi+SiN 7.90E+07 3.17 62.47 -7.05 0.14

sample after a thermal load resistance per square
[ohms] _screw
[%] L* has* b* ∆E 10 1.00E+04 7.41 53.12 -2.4 -12.31 17.5 11 3.00E+04 8.4 53.64 4.07 -8.59 15.2 12 1.40E+04 6.25 55.52 -1.46 -7.64 11.8

List of reference symbols

1 glass or vitroceramic element 10 glass or glass-ceramic substrate 11, 12 sides or major faces of the element or substrate 100 region of element or substrate not coated with coating 2 101 region of the element or of the substrate provided with the coating 2 2 coating, light shielding coating 2a, 2b, 2c layers of the layer system 20 layer system 3 other coating 4 masking layer 5 structuring layer 501 region in which the structuring layer is at least partly applied 60 household appliance and/or heater 70 display and/or operating element 80 sensor

Claims (17)

Glass or glass-ceramic element (1) of the plate type comprising a glass or glass-ceramic substrate (10) of the plate type and also a coating (2) arranged at least in regions on at least one main face (11, 12) of the substrate in glass or vitroceramic (10),
wherein the coating (2) comprises a metallic component and a semi-metallic component,
wherein the glass or glass-ceramic substrate (10) has a transparent configuration,
wherein the coating (2) has a sheet resistance greater than 1 MΩ,
wherein the glass or glass-ceramic element (1), at least in a region (101) in which the coating (2) is arranged, has a light transmission factor, τ _vis , of between 0.5% and 10% , preferably between 0.5% and 5%. A glass or glass-ceramic element (1) according to claim 1, in which the coating (2) has a reflective configuration, "reflecting" referring more particularly to a coating (2) when the glass or glass-ceramic element (1) in the at least one region (101) has one of the following properties:
- an average reflection in the visible spectral range, that is to say from 380 nm to 780 nm, of between 10% and 30%, achieved more particularly for a coating (2) which is configured as a single layer, or
- an average reflection in the visible spectral range, that is to say from 380 nm to 780 nm, of between 20% and 70%, achieved more particularly for a coating (2) which is configured as a system of layers ( 20), more particularly comprising at least three partial layers (2a, 2b, 2c),
in which more particularly these values indicated above are reached when the glass or vitroceramic element (1) has a smooth configuration on the main face (11, 12) on which the coating (2) is arranged, "smooth" also relating more particularly to a main face (11, 12) obtained by rolling with an unstructured roller, and/or to a main face (11, 12) having a roughness, more particularly a roughness R _a , of less than 1 μm,
or in which the main face (11, 12) on which the coating (2) is arranged has a roughness of between 1 µm and 5 µm and is preferably structured and the glass or vitroceramic element (1) in the region ( 101) has an average reflection in the visible spectral range, i.e. between 380 nm and 780 nm, of between at least 2% and at most 20%, or
a gloss, preferably determined with the Rhopoint Qs gloss meter, of at least 87 GU, preferably at least 100 GU, more particularly according to a measuring angle of 20°, of at least 93 GU, preferably at least 100 GU , more preferably at a measuring angle of 60°, and at least 97 GU more particularly preferably at a measuring angle of 85°, wherein the main face or the side on which the coating is placed has a roughness, more particularly a roughness R _a , of between 1 µm and 5 µm and is preferably structured,
Where
a gloss, preferably determined with the Rhopoint Qs gloss meter, of at least 500 GU, preferably at least 700 GU, more particularly according to a measuring angle of 20°, of at least 200 GU, preferably at least 250 GU , more preferably at least 270 GU and very preferably at least 300 GU, more particularly preferably according to a measurement angle of 60°, and at least 99 GU more particularly preferably according to a measurement angle of 85°, in which more particularly these values indicated above are achieved when the glass or vitroceramic element has a smooth configuration on the main face or the side on which the coating is arranged, "smooth" also referring more particularly to a main face or a side, for example the upper side or a lower side of a plate, which is obtained by rolling with an unstructured roll, and/or a main face (or a side, such as one side s upper or lower side) having a roughness, more particularly a roughness R _a , of less than 1 μm. A glass or glass-ceramic element (1) according to any one of claims 1 and 2, in which the coating (2) has a simultaneous tactile and reflective configuration. Glass or glass-ceramic element (1) according to any one of Claims 1 to 3, in which the glass or glass-ceramic element (1), at least in the region (101) in which the coating (2) is arranged, has a color locus in the CIEL*a*b* system with L* greater than 55 and a*,b* in the range of -12 to +12, preferably -10 to +10, more preferably -5 to +5, preferably determined or determinable when measuring color locus with a color locus instrument, preferably determined when measuring against a black well, more preferably with a Konica- Minolta CM-700d, wherein the coating (2) is disposed on the main face (11, 12) of the glass or glass-ceramic substrate (10) which faces away from the color locus instrument. Glass or vitroceramic element (1) according to any one of Claims 1 to 4, in which the coating (2) has a thickness of less than 1000 nm and preferably at least 20 nm. Glass or vitroceramic element (1) according to any one of Claims 1 to 5, in which the coating (2) has a constant thickness. Glass or glass-ceramic element (1) according to any one of Claims 1 to 6, in which
- the coating (2) has a metallic configuration, and
wherein preferably the amount of the O and/or N elements in the coating (2) is in each case less than 4% by weight, preferably in each case less than 2% by weight, and
wherein preferably the semi-metallic component comprises Si and the semi-metallic component comprises Al and
wherein more preferably the coating (2) has an Si content greater than 70% by weight and an Al content less than 30% by weight. Glass or glass-ceramic element (1) according to any one of Claims 1 to 6, in which
- the coating (2) has a non-metallic configuration and
wherein preferably the semi-metallic component comprises Si and the metallic component comprises Al, and
wherein the coating (2) more preferably comprises the elements O and/or N, wherein the N content of the coating (2) is preferably at least 4% by weight and more preferably greater than 4% by weight and/or the O content of the coating (2) is preferably greater than 10% by weight. A glass or glass-ceramic element (1) according to claim 8, wherein the Si content of the coating (2) is greater than 40% by weight and the Al content of the coating (2) is less than 60% by weight. Glass or glass-ceramic element (1) according to any one of Claims 1 to 9, having at least one of the following characteristics:
- the glass or glass-ceramic element (1) comprises another coating (3), which is arranged on the at least one main face (11, 12) at least in regions between the glass or glass-ceramic element (10) and the coating (2),
- the glass or vitroceramic element (1) comprises a masking layer (4) which is arranged at least by regions on the coating (2),
- the coating (2) has a refractive index n of at least 2 or more and/or an absorption coefficient of at least 0.1 or more at a wavelength of 550 nm,
- the coating (2) has an amorphous configuration,
- the glass or glass-ceramic element (1) comprises, on at least one main face (11, 12), a structuring layer (5) which is preferably placed between the coating (2) and the glass or glass-ceramic substrate (10), more preferably adjacent to the glass or glass-ceramic substrate (10),
- the glass or vitroceramic element (1) is configured as a glass element and, in the region (101) in which the coating (2) is arranged, has a light transmission factor, τ _vis , of between 0, 5% and 5%, preferably 0.5% and 3.5%, more preferably between 0.5% and 1.5%,
- the glass or glass-ceramic element (1) is configured as a glass-ceramic element and, in the region (101) in which the coating (2) is arranged, has a light transmission factor, τ _vis , of between 0, 5% and 10%, preferably between 0.5% and 5%, more preferably between 2% and 5%. Glass or glass-ceramic element (1) according to any one of Claims 1 to 10, having a thermal resistance, more particularly a stability of the optical properties, as follows:
- after a thermal load of 80 h of the glass or glass-ceramic element (1) at 390°C, the difference in light transmission factor of the glass or glass-ceramic element (1) in the region (101) after a thermal load and before a thermal load is at most 5% absolute, preferably at most 3% absolute, and/or
- after an 80 h thermal load of the glass or glass-ceramic element (1) at 390°C, the difference in color locus of the glass or glass-ceramic element (1) in the region (101), ΔE, is at most 20, preferably at most 10, more preferably at most 5 and very preferably at most 2, in which ΔE is determined as follows:
,
wherein the color locus E _vT relates to the color locus of the glass or glass-ceramic element (1) in the region (101) before a thermal load and is given by the colorimetric coordinates a* _vT , b* _vT and L * _vT , and the color locus E _nT is the color locus of the glass or glass-ceramic element (1) in the region (101) after a thermal load and is given by the colorimetric coordinates a* _nT , b* _nT and L* _nT , and is preferably determined in each case when measured against a black well, more particularly with a Konica-Minolta CM-700d spectrophotometer. Glass or glass-ceramic element (1) according to any one of Claims 1 to 11, in which the coating (2) is configured as a layer system (20) comprising partial layers (2a, 2b, 2c), preferably comprising three partial layers, wherein at least two partial layers (2a, 2c) comprise at least one metallic component and at least one semi-metallic component and enclose at least one intermediate layer (2b), wherein the at least one intermediate layer (2b) comprises a dielectric material and preferably the at least one intermediate layer (2b) has a refractive index n at 550 nm which is lower than that of the at least two other partial layers (2a, 2c), and in addition, preferably, the absorption coefficient k of the intermediate layer (2b) at 550 nm is lower than the absorption coefficient k at 550 nm of the at least two other partial layers (2a, 2c). Domestic electrical and/or heating appliance (60) comprising a glass or vitroceramic element (1) according to any one of Claims 1 to 12. Household and/or heating appliance (60) according to Claim 13, comprising at least one display and/or operating element (70) and/or one sensor (80). Process for producing a glass or glass-ceramic element (1), preferably a glass or glass-ceramic element (1) according to any one of claims 1 to 12, comprising the steps of
- provision of a glass or glass-ceramic substrate (1) of the plate type having a transparent configuration,
- introduction of the glass or glass-ceramic substrate (1) into a coating chamber,
- providing a target comprising at least one semi-metallic component and/or at least one metallic component in the coating chamber,
- establishment of a pressure in the coating chamber, in which the pressure is between at least 5*10 ^-4 mbar and at most 5*10 ^-2 mbar,
- sputter coating, in which the sputtering can take place as direct current sputtering or as alternating current sputtering, for example as medium-frequency or high-frequency sputtering,
to give a plate-like glass or glass-ceramic element (1) comprising a plate-like glass or glass-ceramic substrate (10) and also a coating (2) arranged at least in regions on at least one main face (11, 12) glass or glass-ceramic substrate (10),
wherein the coating (2) comprises a metallic component and a semi-metallic component and has a sheet resistance greater than 1 MΩ, and wherein the glass or glass-ceramic element (1), at least in one region (101) in which the coating (2) is disposed, has a light transmittance, τ _vis , of between 0.5% and 10%, preferably between 0.5% and 5%, preferably based on a thickness of glass or vitroceramic substrate (10) of 4 mm. Glass or glass-ceramic element (1), preferably glass or glass-ceramic element (1) according to one of Claims 1 to 12, produced or capable of being produced in a process according to Claim 15. Use of a glass or glass-ceramic element according to any one of claims 1 to 12 or 16 and/or produced or capable of being produced in a process according to claim 15 as a masking plate for a household appliance and/or heating (60), more particularly as a masking plate for a cooker, or as an oven window, or as a manhole cover, or as an inspection window in a refrigerator, or as an inspection window in a microphone apparatus -waves, or as the front glass of an operating element, more particularly of an operating element of a coffee machine or in an oven, or as a worktop in a kitchen or a laboratory unit, such as, for example, a table-dryer or a table, or in a consumer electronic device, for example in a smartphone.