Cover panel with colour-neutral coating

Abstract

A cover panel for a fitout article or article of equipment for a kitchen or laboratory is provided. The cover panel includes a glass or glass ceramic substrate and a coating on one side of the substrate. The substrate and the coating together have a light transmittance of 1% to 70%. The coating has a colour locus in the CIELAB colour space within the range of coordinates L* of 20 to 65, a* of −6 to 6 and b* of −6 to 6. The colour locus of the D65 standard illuminant light, after passing through the substrate and the coating, is within a white region W1 determined in the chromaticity diagram CIExyY-2° by the following coordinates: TABLE-US-00001 White region W1 x Y 0.27 0.21 0.22 0.25 0.32 0.37 0.45 0.45 0.47 0.34 0.36 0.29.

Claims

1. A cover panel for a fitout article or article of equipment for a kitchen or laboratory, comprising: a glass or glass ceramic substrate; and a coating on one side of the substrate, wherein the substrate and the coating together have a light transmittance of 1% to 70%, wherein the coating has a colour locus in the CIELAB colour space with the coordinates L* of 20 to 65 and a* of −6 to 6 and b* of −6 to 6, measured in reflectance with D65 standard illuminant light against a black trap in transmission through the substrate, and wherein the cover panel has a colour locus of the D65 standard illuminant light, after passing through the substrate and the coating, is within a white region W1 determined in the chromaticity diagram CIExyY-2° by the following coordinates: TABLE-US-00008 White region W1 x Y 0.27 0.21 0.22 0.25 0.32 0.37 0.45 0.45 0.47 0.34 0.36 0.29.

2. The cover panel of claim 1, wherein the cover panel does not include a black-body compensation filter.

3. The cover panel of claim 1, wherein the colour locus in the CIELAB colour space has the coordinates 22≤L*≤35, with −4≤a*≤4, and with −4≤b*≤4.

4. The cover panel of claim 1, wherein the colour locus in the CIELAB colour space has the coordinates 45≤L*≤65, with −4≤a*≤4, and with −4≤b*≤4.

5. The cover panel of claim 1, wherein the colour locus of the D65 standard illuminant light is within a white region W2 determined in the chromaticity diagram CIExyY-2° by the following coordinates: TABLE-US-00009 White region W2 x Y 0.25 0.27 0.32 0.36 0.41 0.42 0.42 0.36 0.35 0.31 0.27 0.24.

6. The cover panel of claim 1, wherein the substrate together with the coating has a transmission at a wavelength of 1500 nm of at least 30%.

7. The cover panel of claim 1, wherein the substrate together with the coating has a transmission at at least one wavelength in a range between 850 nm and 1000 nm of at least 3%.

8. The cover panel of claim 1, wherein the substrate together with the coating has a transmission at at least one wavelength in a range between 3.25 μm and 4.25 μm of at least 10%.

9. The cover panel of claim 1, wherein the substrate is a glass ceramic substrate having a coefficient of thermal expansion CTE between 20 and 300° C. of less than ±2.5×10.sup.−6/K.

10. The cover panel of claim 1, wherein the substrate is a glass substrate having a coefficient of thermal expansion CTE between 20 and 300° C. of 3.5 to 6×10.sup.−6/K and a glass transition temperature T.sub.g of 500 to 650° C.

11. The cover panel of claim 1, wherein the coating has a sheet resistance of at least 1 kω/□ at a test voltage of 1000 V.

12. The cover panel of claim 1, where the coating has an average spectral reflectance in a wavelength range of 380 to 780 nm of at most 10% measured in transmission through the substrate.

13. The cover panel of claim 12, wherein the coating has a ratio of highest spectral reflectance to lowest spectral reflectance in the wavelength range of 380 to 780 nm that equals 1 to 5.

14. The cover panel of claim 1, wherein the substrate and the coating together have a haze of less than 5% measured to ASTM-D1003.

15. The cover panel of claim 1, wherein the coating comprises a material system selected from a group consisting of: a spinel, a cermet, a carbide, and a carbonitride.

16. The cover panel of claim 1, the coating comprises a material system selected from a group consisting of: aluminium spinels, chromium spinels, iron spinels, titanium spinels, cobalt spinels, and CoFeMnCr spinels.

17. The cover panel of claim 1, wherein the coating comprises a cermet with an oxidic matrix composed of SiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2, or mixed oxides thereof and a metallic component composed of Ti, Si, Al, Mo, Zr, Cu, Nb, Co, Cr, W, Ta, Ni, B or an alloy of at least two of these metals.

18. The cover panel claim 1, wherein the coating consists of an MoSiO.sub.x cermet.

19. The cover panel claim 1, wherein the coating comprises a cermet with an oxidic matrix composed of SiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2, or mixed oxides thereof and a metallic component composed of Ti, Si, Al, Mo, Zr, Cu, Nb, Co, Cr, W, Ta, Ni, B or an alloy of at least two of these metals and does not contain any further constituents other than unavoidable impurities.

20. The cover panel claim 1, wherein the D65 standard illuminant light, after passing through the substrate and the coating, is homogenous.

21. A cover panel for a fitout article or article of equipment for a kitchen or laboratory, comprising: a glass or glass ceramic substrate; and a coating on one side of the substrate, wherein the substrate and the coating together have a light transmittance of 1% to 70%, wherein the coating has a colour locus in the CIELAB colour space with the coordinates L* of 22 to 35 and a* of −4 to 4 and b* of −6 to 6, measured in reflectance with D65 standard illuminant light against a black trap in transmission through the substrate, and wherein the cover panel has a colour locus of the D65 standard illuminant light, after passing through the substrate and the coating, is within a white region W1 determined in the chromaticity diagram CIExyY-2° by the following coordinates: TABLE-US-00010 White region W1 x Y 0.27 0.21 0.22 0.25 0.32 0.37 0.45 0.45 0.47 0.34 0.36 0.29.

22. A cover panel for a fitout article or article of equipment for a kitchen or laboratory, comprising: a glass or glass ceramic substrate; and a coating on one side of the substrate, wherein the substrate and the coating together have a light transmittance of 1% to 70%, wherein the coating has a colour locus in the CIELAB colour space with the coordinates L* of 45 to 65 and a* of −4 to 4 and b* of −6 to 6, measured in reflectance with D65 standard illuminant light against a black trap in transmission through the substrate, and wherein the cover panel has a colour locus of the D65 standard illuminant light, after passing through the substrate and the coating, is within a white region W1 determined in the chromaticity diagram CIExyY-2° by the following coordinates: TABLE-US-00011 White region W1 x Y 0.27 0.21 0.22 0.25 0.32 0.37 0.45 0.45 0.47 0.34 0.36 0.29.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1a shows a chromaticity diagram of the CIExyY colour space.

(2) FIG. 1b shows an enlarged detail from FIG. 1a.

(3) FIG. 2 shows a spectral reflectance of Examples 1 and 5.

(4) FIG. 3 is a schematic diagram of an embodiment of a fitout article or article of equipment with a cover panel of the invention in cross section.

DETAILED DESCRIPTION

(5) FIG. 1a shows a chromaticity diagram of the CIExyY colour space with 2° standard observer (CIExyY-2°).

(6) FIG. 1a shows the following elements: the black-body curve as a dotted line, the two white regions W1 and W2 as dashed lines, the white region W3 as a dashed line with dots, the colour coordinates of D65 standard illuminant light as a dot, the colour coordinates of D65 standard illuminant light after passing through working examples 1-10 as squares, and the colour coordinates of D65 standard illuminant light after passing through comparative example V1 as x.

(7) FIG. 1b shows an enlarged detail from FIG. 1a.

(8) Every point on the black-body curve corresponds to the colour locus of the light emitted by a black-body radiator at a defined temperature, called the colour temperature. This curve is of particular relevance to human perception since the sun likewise corresponds to a black-body radiator and hence the colour of sunlight is on the black-body curve. According to the position of the sun, the colour locus moves between cooler and warmer colour loci; a colour temperature of 20 000 K corresponds to a clear sky and a temperature of 3500 K to evening sunlight shortly before the commencement of dusk. Colour loci at or close to the black-body curve are therefore perceived as white and particularly natural.

(9) All examples are within the white region W1, distributed along the black-body curve. Example 5 produces a particularly warm colour temperature at somewhat below 3000 K. This corresponds roughly to an incandescent lamp with a power of 200 W.

(10) FIG. 2 shows the spectral reflectance of Examples 1 (“spinel”, solid line) and 5 (“MoSiOx”, short-dashed line) and of an SiC coating of the invention (“SiC”, long-dashed line) over the entire visible spectral range of 380 to 780 nm.

(11) All three examples shown have very low spectral reflectances over the entire visible spectral region of less than 10%, and an average of about 5%. In addition, the curves have a very flat profile and have only minimal differences between the maximum and minimum reflectances.

(12) Given such low reflectances, light that passes through such a cover panel can be very well perceived on the other side even in the case of very bright ambient light.

(13) Since the curves have a very flat profile, the colour locus of reflected light is not shifted and the cover panel looks particularly colour-neutral.

(14) FIG. 3 contains a schematic diagram of one embodiment of a fitout article or article of equipment (1) with a cover panel (3) of the invention in cross section. The cover panel (3) here separates sections of the interior (4) of the article (1) from the exterior (5). The cover panel consists, in the diagram, of a glass or glass ceramic substrate with the coating (2) atop the substrate. Collectively, the substrate and coating (2) have a light transmittance of 1% to 70%. The colour locus of the coating (2) in the CIELAB colour space is in the region of the coordinates L* of 20 to 65 and a* of −6 to 6 and b* of −6 to 6, measured in reflectance with D65 standard illuminant light against a black trap and in transmission through the glass or glass ceramic substrate. The colour locus of D65 standard illuminant light after passing through the glass or glass ceramic substrate and the coating (2) is within the white region W1.

(15) Fitout articles or articles of equipment for kitchens or laboratories having cover panels of the invention may contain a multitude of components in their interior.

(16) The articles may, for example, have one or more heating elements for heating an article, for example a pan, in the exterior or even in the interior of the article. These may especially be radiative heating elements, induction heating elements or microwave generators.

(17) The articles may have display elements and lighting elements such as point, linear or areal light sources. These include, for example, LEDs, optical fibres and OLEDs. These light sources can emit in a particular colour, especially white, red, green and/or blue, or else variable colours. The usable display elements include, for example, graphic displays or segment displays. The graphic displays include, for example, TFT displays, especially LCDs or OLED displays. The segment displays especially include 7-segment displays. More particularly, it is also possible to provide red-illuminating TFT displays.

(18) Between these lighting elements and the cover panel, it is possible for additional colour filters to be provided, for example in order to be able to utilize a white LED for production of a coloured lighting effect with a defined colour locus and high colour saturation.

(19) Lighting elements may especially also be disposed in the hot region in the vicinity of heating elements. In this case, especially for the production of white lighting effects in the exterior of the article, it is advantageous that no temperature-sensitive black-body compensation filters are required.

(20) The articles may have cooling aggregates, for example Peltier elements, in thermal contact with the cover panel in order to produce a cooling surface, for example for cooling of foods or chemicals, on the exterior-facing side of the cover panel.

(21) The article may have various sensors, for example capacitative touch sensors for control or infrared sensors for gesture control or for measurement of the temperature of hot articles in the exterior, for example hot pans. Such sensors may have been printed, pressed, bonded or adhesive-bonded, or arranged in some other way, on the underside or reverse side of the substrate. This is particularly true of touch sensors.

(22) In addition, the article may have microphones and cameras, for example for voice control or user recognition and authentication. This may be particularly advantageous in laboratories, for example, if the article may be used only by correspondingly trained personnel.

(23) The article may have various interfaces for communication, for example WLAN, Bluetooth or NFC modules or infrared interfaces. By means of such interfaces, the article can be connected, for example, either to the Internet or to other articles in its vicinity, for example pans with a corresponding interface or other electronic devices. More particularly, for control and communication, it can be connected to a mobile electronic device, such as a mobile phone or a tablet.

(24) The article may contain a device for wireless energy transmission from articles in the exterior, especially by means of induction coils and in accordance with the Qi standard.

(25) The cover panel may have coatings on the exterior-facing side, for example anti-scratch layers, anti-reflection layers, anti-glare layers, decorative layers, easily cleanable layers or infrared-reflecting layers, provided that these do not alter the essential optical properties of the cover panel.

(26) The cover panel may have cutouts, for example recesses for sinks or down-draft fume hoods or bushings for pipelines.

(27) All these constituents may be present individually or in combination.

(28) It has been found that, surprisingly, it is possible with a cover panel of the invention to fulfill the multitude of use-specific demands particularly efficiently. The optical properties can be adjusted such that lighting means mounted beneath or behind the cover panel can be seen clearly, brightly and with the desired colour impression. At the same time, however, viewing through the cover panel can be sufficiently prevented. In this way, it is possible to achieve a dead front effect in a particularly efficient manner. This means that electronic components, even in the switched-off state, are not visible through the cover panel. Particularly in the switched-off state, this gives rise to a particularly homogeneous and pleasing look of the covering means. Nevertheless, the covering means are combinable with a multitude of different sensors. These include, for example, capacitative or inductive sensors and infrared sensors at various wavelengths.