Glass or glass-ceramic articles with improved visibility for electro-optical display elements and methods for their manufacture

Abstract

Glass or glass-ceramic element with improved visibility for electro-optical display elements (1) in at least one area (5), comprising a top (11) and a bottom (12), wherein the top (11) is the side of the glass or glass-ceramic element (1) which faces the user during use, and the bottom (12) is the side which faces away from the user during use, and on the bottom (12) at least in the area (5) with improved visibility for electro-optical display elements at least one layer (3) which has a content of scattering particles between 0.1 and 25 wt.-% and a silicone resin, wherein the transmission Tbin the area (5) with improved visibility for electro-optical display elements is between 15 and 30% of the transmission Tueines uncoated area (6) of the glass or glass-ceramic element (1), wherein the scattering particles have a mean primary grain size between 200 and 800 nm and a refractive index greater than 1.6 at a wavelength of 560 nm and wherein the thickness of the layer (3) is between 4 and 10 µm.

Description

Field of invention

[0001] The invention relates to glass or glass-ceramic articles, for example for use as a cooking surface, which have improved visibility for electro-optical display elements arranged below them, and furthermore to a method for their manufacture. Background of the invention

[0002] Glass or glass-ceramic elements have been used for many years as cooktops or control panels for household appliances. The integration of display elements into such cooktops or control panels is becoming increasingly important due to advancing digitalization, but also for aesthetic reasons.

[0003] One difficulty in integrating such displays is that their visibility is often impaired by glass or glass-ceramic elements, which can be either colored or uncolored. For example, when viewed at an angle of 80° to the surface normal of the glass or glass-ceramic element, displays are either not visible or only very poorly visible. Furthermore, the shift in viewing angle leads to the phenomenon of "optical wander," meaning that when viewed at an angle of 80°, the position of the light source appears to change due to the projection of the light source onto the covering glass or glass-ceramic element.

[0004] It is also bothersome that when using multiple light sources, especially point sources, these are often perceived as separate. A much more homogeneous light distribution is often desirable, for example, to illuminate or backlight an area evenly.

[0005] Additionally, especially with glass-ceramic elements, which often have a textured underside for improved handling, the difficulty often arises that high contour sharpness is not possible, since the structures inherent in the glass-ceramic element due to the textured underside lead to a distortion of the display due to light refraction.

[0006] Various solutions are known from the state of the art for integrating electro-optical display elements into control panels and / or cooking surfaces made of glass or glass-ceramic.

[0007] For example, German patent DE 10259 297 B4 describes how light is extracted from a light guide via diffusing elements. This light guide is positioned at a certain distance from the cooking surface. While this method achieves a relatively homogeneous light distribution, the distance between the light guide and the backlit glass element results in a strong viewing angle dependency, such that when viewed from the side, the light is either not perceived or only very poorly perceived, and the indicated position appears to "wander."

[0008] Furthermore, US patent application US 2012 / 118870 A describes a lighting unit positioned below a glass ceramic. Due to the distance to the glass ceramic, a strong dependence on the viewing angle also occurs here, and the "optical wander" described above also takes place.

[0009] US patent application US 2013 / 286630 A discloses light-guiding elements. According to a specific embodiment, these light-guiding elements can be used in combination with a diffusing layer and various masking elements. The diffusing layer serves to provide more homogeneous illumination of the area to be backlit. However, no precise details are given regarding the structure of this diffusing layer. Furthermore, no statements are made regarding the viewing angle dependency of the resulting illumination. The light-guiding elements, which contain diffusing layers, are positioned at a certain distance from the underside of the glass-ceramic, so that, as with other applications, the display elements appear to "move" due to changes in the viewing angle.

[0010] There is therefore a need for glass or glass-ceramic elements in which, at least in one area, improved visibility for electro-optical display elements is achieved in such a way that homogeneous illumination of an area to be backlit is provided while at the same time the illumination is largely independent of the viewing angle. Object of the invention

[0011] The invention aims to provide a glass or glass-ceramic element with improved visibility for electro-optical display elements, at least in a partial area. A further aspect of the invention relates to a method for manufacturing such a glass or glass-ceramic element. Summary of the invention

[0012] The invention is solved in a surprisingly simple manner by a glass or glass-ceramic element according to claim 1 and by a method according to claim 14. Preferred embodiments are found in the dependent claims.

[0013] The glass or glass-ceramic element according to the invention, with improved visibility for electro-optical display elements in at least one area, has a top and a bottom. The top side of the glass or glass-ceramic element that faces the user during use is referred to as the top side. Correspondingly, the bottom side of the glass or glass-ceramic element that faces away from the user during use is referred to as the bottom side. At least in the area of ​​the glass or glass-ceramic element with improved visibility for electro-optical display elements, a layer is arranged on the bottom side, which has a content of scattering particles between 0.1 and 25 wt.% and a silicon-based binder. The transmission T bFor electromagnetic radiation in the wavelength range of 380 to 780 nm, the transmission in the area with improved visibility for electro-optical display elements is between 15 and 30% of the transmission of an uncoated area of ​​the glass or glass-ceramic element.

[0014] The layer comprising scattering particles is also referred to as a scattering layer within the scope of the present invention. The terms coating and layer are also used synonymously.

[0015] The improved visibility of the electro-optical display element in the glass or glass-ceramic elements of the present invention is manifested in the fact that a. both the viewing angle dependence of the perception of the lighting through the glass or glass-ceramic element ( 1 ) is reduced through it, so that the illumination is perceptible even when viewed from the side, as well as b. the intensity distribution of the illumination is more homogeneous when viewed at an angle of + / - 5° to the normal to the top surface of the glass or glass-ceramic element, and / or c. Display elements located on the side facing away from the viewer differ in their display position when viewed at an angle α to the surface normal, compared to the display position when viewed perpendicularly, by only a deviation w. α , which can be derived from the following equation This results in a shift compared to the display location when viewed perpendicularly. Here, α denotes the angle formed between the viewing direction and the surface normal, and D is the thickness of the glass or glass-ceramic element.

[0016] Optionally, according to one embodiment of the invention, the representation of fine structures on the side of the glass ceramic facing away from the viewer is also improved, in particular so that a resolution of 120 dpi or more of the display element is achievable.

[0017] According to a further embodiment of the invention, the haze value in the area of ​​the glass or glass-ceramic element with improved visibility for electro-optical display elements is greater than 95%. The haze value represents a measure of light scattering and is determined by measurement with the Haze Guard Dual measuring device, which calculates the scattered light (haze) from the total transmission of the samples.

[0018] To evaluate the light point resolution, the brightness values ​​can be taken from the photographic images of the light bars ( Fig.6) can be evaluated. A suitable parameter is the ratio of maximum intensity to minimum intensity along the connecting line of the LEDs between the two outer LEDs (I). min / I max ). (Corresponding data are provided in Table 2 of the latest amendments to the first draft.) A comparison with a subjective assessment shows that for conditions I min / I max > 0.95 the LED is no longer considered "visible". Given the aforementioned geometric requirements for the lighting unit, the following results for the solutions according to the invention: I min / I max > 0.95.

[0019] The area with improved visibility for electro-optical display elements can be further subdivided. In certain embodiments of the invention, individual elements of an electro-optical display element arranged below the glass or glass-ceramic element, such as point light sources, may still be perceived, for example, as a "halo" that surrounds the central, brighter core belonging to the respective individual element with lower brightness. The diameter of such a halo is typically a few millimeters, for example, 4 mm. Such a halo can be approximately described by the light intensity present in this area.The light intensity in this sub-area is at least 5 percentage points higher than the light intensity in the other areas of the enhanced visibility region and can be approximated by the dimensions of the light spot falling on the underside of the glass or glass-ceramic element. Thus, the enhanced visibility region for electro-optical display elements can be divided into at least two sub-areas: the sub-area that lies outside the halo (approximately outside the radius of the light spot falling on the underside) and the sub-area that lies within the halo or within the radius of the light spot falling on the underside.

[0020] According to a further embodiment, the glass or glass-ceramic element is designed such that the illumination intensity I of the display of an electro-optical display element arranged below its underside in the area of ​​the glass or glass-ceramic element with improved visibility, normalized to the illumination intensity I0, is at least 0.9 times the illumination intensity I0 which is perpendicular to the at least one light source.

[0021] When using the glass-ceramic embodiment according to the invention, an electro-optical display element consisting of at least one light source can be used. When using essentially point-shaped LEDs as light sources, the ratio of the distance a between the glass or glass-ceramic element and the electro-optical display element, or the at least two point-shaped light sources of the electro-optical display element, to the distance d between the at least two point-shaped light sources is preferably 1 or more. Therefore, preferably: a / d ≥ 1

[0022] According to a further embodiment of the invention, the scattering particles have a mean primary grain size between 200 and 800 nm. Scattering particles are defined here as particles of materials that are colorless, i.e., that exhibit a virtually constant absorption coefficient for electromagnetic radiation over the wavelength range of 380 to 780 nm, and a refractive index greater than 1.6 at a wavelength of 560 nm. Furthermore, it is also possible to use mixtures of different particles acting as scattering particles.

[0023] The scattering particles most preferably comprise TiO2, ZrO2, ZnO, ZnS, PbCO3, BaSO4 and / or mixtures thereof. For example, the scattering particles can also comprise lithopone, which is a mixture of BaSO4 and ZnS and optionally up to 2 wt% ZnO, with different mixing ratios between BaSO4 and ZnS being possible.

[0024] According to a further preferred embodiment of the invention, the silicon-containing binder comprises a silicone resin. More preferably, this is a polyester-modified silicone resin.

[0025] Within the scope of the present invention, the term silicone resin refers to compounds in which crosslinkable molecules are present, wherein these molecules have silicon atoms linked together by oxygen atoms. Furthermore, these substances also contain organic components that are likewise bonded to the silicon atoms, as well as optionally further organic functional groups. Such a silicone resin is capable of curing through polymerization. Therefore, the term silicone resin also includes organic polysiloxanes.

[0026] According to a preferred embodiment of the invention, the layer comprises a chromophore or a mixture of chromophores. For example, the chromophore can be configured as a pigment or as a dye, such as a luminescent pigment or dye. In particular, such a pigment can be configured as a y-doped Ce-YAG or LuAG particle. In this way, the desired color of the illumination can be set by selecting suitable illumination, i.e., by adjusting the spectrum of the emitted electromagnetic radiation, as well as by taking into account the scattering properties of the layer, the luminescence properties of the luminescent chromophore(s), and the transmission of the glass or glass-ceramic element.It is also possible to modify this color tone by adding further color filters, for example in the form of color-filtering layers, between the underside of the glass ceramic and the electro-optical display element.

[0027] According to a further embodiment of the invention, at least one further layer is therefore arranged between the display element and the glass or glass-ceramic element.

[0028] This additional layer can have different functions. For example, it can be designed as an optically effective layer, such as a color filter. It can also have masking functions, blocking the passage of any scattered light beneath the glass or glass-ceramic element, thus preventing areas of the glass-ceramic outside the area backlit by the display element from being visible from above.

[0029] In particular, according to one embodiment of the invention, this at least one further layer can be configured as an immersion layer. An immersion layer is understood here to be a layer that at least partially fills any structures located on the underside of the glass or glass-ceramic element in order to reduce their visibility.

[0030] Preferably the thickness of the layer comprising scattering particles is between 1 and 50 µm, preferably between 4 and 10 µm.

[0031] Another aspect of the invention relates to a method for manufacturing a glass or glass-ceramic article with improved visibility for electro-optical display elements. The method comprises the following steps: a. Providing a glass or glass-ceramic element with a top and a bottom b. Providing a liquid coating material comprising at least a silicon-based binder, a solvent and spreading particles, c. Applying the liquid coating material to at least one area of ​​the underside of the glass or glass-ceramic element, d. Curing of the coating material, resulting in cross-linking of the silicon-containing binder.

[0032] Preferably, the liquid coating material is applied by rollers, pouring, doctor blades, or by a printing process, preferably screen printing or inkjet printing. In a further embodiment, textured substrates can also be coated with the liquid coating material by a spraying process without an additional immersion layer.

[0033] According to a preferred embodiment, the coating material is applied using a screen printing process, wherein the application is carried out using a screen with a thread count between 200 and 100 threads per centimeter, preferably with a thread count of 180, 140 and 120 threads per centimeter.

[0034] The coating material can be cured thermally, by IR radiation, or by UV radiation. Thermal curing is preferred, however, carried out at a temperature between 375 °C and 150 °C for a duration of at least 10 minutes and up to a maximum of 2 hours. Curing between 275 °C and 180 °C is more preferred. Curing at 250 °C for a duration of 30 minutes to one hour is particularly preferred.

[0035] The liquid coating agent, which is also referred to as varnish within the scope of the present invention, is transformed into the layer or coating layer comprising the scattering particles by hardening.

[0036] According to a further embodiment of the invention, the at least one silicon-containing coating material is designed as a silicone resin. Preferably, the silicone resin is a condensation-curing silicone resin; particularly preferably, it is a polyester-modified condensation-curing silicone resin.

[0037] According to a further preferred embodiment of the invention, the silicone resin comprises functional groups. For example, modifications using polyesters, polyacrylates, epoxides, vinyls, acrylates, methacrylates, or alkanes could be employed as functionalized organic groups.

[0038] According to a further preferred embodiment of the invention, the coating agent comprises at least one surface-active additive, preferably a surface-active deaerating and / or defoaming additive.

[0039] In the context of the present invention, a surface-active additive is understood to be a substance which is added to a liquid coating material in small quantities, i.e., in the range of less than 9 wt.%, based on the total mass of the coating material, in order to reduce the content of bubbles or bubble agglomeration (foam) in the coating material, for example by dissolving existing bubbles. In particular, so-called defoaming and deaerating additives are to be understood as surface-active additives within the meaning of the present invention.

[0040] Preferably, the total content of additives, based on the mass of the coating material, is between 0.5 and 9 wt.%.

[0041] Furthermore, according to a further embodiment of the invention, the coating agent comprises a hydrolysate of an organic compound of a metal and / or a semimetal, preferably a hydrolysate of an organosilicon compound. Examples

[0042] The invention is explained below using exemplary embodiments. Example 1

[0043] 0.08 mol of glycidyloxypropyltriethoxysilane (GPTES) and 0.02 mol of tetraethoxysilane (TEOS) are hydrolyzed with 0.02 mol of water, which may also be acidified, for example, by the addition of para-toluenesulfonic acid. Any low-boiling solvent present, such as ethanol produced during hydrolysis, is then removed by rotary evaporation. This yields 23.0 g of hydrolysate. To this, 11.5 g of polyester-modified silicone resin are added while stirring continuously, along with 1.0 g of an antifoaming agent, 1.7 g of diethylene glycol monoothyl ether, and 6.8 g of TiO₂ particles.

[0044] The resulting coating material is applied to the textured underside of a glass-ceramic element using a screen printing process. The textured surface of this underside, in the area where the coating is applied, is at least partially filled with a dielectric substance (so-called immersion layer). A screen with a 180 mesh count (180 threads per centimeter) is used for screen printing the layer containing the scattered particles. Curing takes place at 250°C for one hour, during which the silicon-containing binder cross-links.

[0045] The resulting diffusing layer enabled the visibility of an underlying electro-optical display element even when viewed from a grazing angle. Furthermore, the illumination of the area covered by this layer was homogeneous in the sense that the intensity I of a light source, normalized to the illuminance I0, was at least 0.9 times the luminous intensity I0 across the entire area to be backlit, provided that the distance between the individual light sources was smaller than the distance between the display element and the underside of the glass ceramic.

[0046] Furthermore, the impact resistance of the glass-ceramic samples coated in this way was tested. Impact resistance is defined here as the strength of the glass or glass-ceramic element when subjected to an impact load from above, i.e., in this case, onto the top surface of a glass or glass-ceramic element according to the invention. For this purpose, a so-called ball drop test was performed. At least five samples with lateral dimensions of 10 x 10 cm were used. 2 and had a thickness of approximately 4 mm, with the coating according to the exemplary embodiment. 1The samples were then placed on a rubber-lined support frame, ensuring that the rubber surface was free of glass fragments or similar particles that could potentially damage the glass or glass-ceramic, and that the sample was not clamped to the frame. A steel ball with a diameter of 36 mm and a mass of 200 g was then dropped from a height of 5 cm onto the surface of the sample in a drop test rig. The drop height was measured on the rig between the underside of the steel ball and the top of the sample. The drop height was then increased by 5 cm increments until the sample broke. The last drop height achieved was recorded. The strength was considered sufficient if the average of the last drop heights achieved was greater than 65 cm.

[0047] This ball drop test was performed for the samples of the exemplary embodiment. 1with a value of 110 cm.

[0048] Furthermore, the samples were subjected to a thermal stress of 250°C for a duration of 75 hours. This resulted in no change in the layer properties. Example 2

[0049] 11.5 g of a polyester-modified silicone resin were mixed with 1.0 g of an antifoaming agent and 1.7 g of diethylene glycol monoethyl ether while stirring. 2.8 g of flocculant particles (TiO2) were also added.

[0050] The resulting coating material was applied to the textured underside of a glass-ceramic element using a screen printing process. The textured surface of this underside, in the area where the coating is applied, is at least partially filled with a dielectric substance (so-called immersion layer). A screen with a 180 mesh count (180 threads per centimeter) is used for screen printing. Curing takes place at 250°C for one hour, during which time the silicon-based binder cross-links.

[0051] Here too, the diffusing layer obtained in this way enabled the visibility of an underlying electro-optical display element even when viewed from a grazing angle. Furthermore, the illumination of the area covered by this layer was homogeneous in the sense that the intensity I of a light source, normalized to the illuminance I0, was at least 0.9 times the luminous intensity I0 across the entire area to be backlit, provided that the distance between the individual light sources was smaller than the distance between the display element and the underside of the glass ceramic.

[0052] The strength of the glass-ceramic elements coated in this way was 140 cm. The layers showed no changes in their properties under a thermal load of 270°C for 75 hours. Description of the drawings

[0053] The invention is explained in more detail below with reference to the drawings. Reference numerals of the same type denote identical or equivalent elements.

[0054] They show:

[0055] Fig. 1 and Fig. 2 schematic and not to scale illustrations of embodiments of glass or glass-ceramic elements according to the invention,

[0056] Fig. 3 a further schematic and not to scale illustration of a further embodiment of a glass or glass-ceramic element according to the invention,

[0057] Fig. 4 a representation of the normalized light intensity in the area of ​​a glass or glass-ceramic element that is backlit by a display device,

[0058] Fig. 5 a photographic representation of a backlit glass or glass-ceramic element according to the present invention,

[0059] Fig.6 the photographic representation of backlit areas for different glass ceramic elements, as well as

[0060] Fig. 7 a representation of the phenomenon of optical migration for glass or glass-ceramic elements according to the invention and those not according to the invention.

[0061] In Fig. 1a) is an embodiment of a glass or glass-ceramic element according to the invention. 1 shown. This has a top side. 11 , which faces the user during operation, as well as via a subpage 12 , which is facing away from the user during operation. Below the underside 12 is a display element 2 arranged, which is not shown here. Between this and the underside 12 is a layer comprising scattering particles 3 arranged, which includes a silicon-containing binder. Furthermore, there are additional layers. 41 , 42between the electro-optical display element (not shown here) 2 as well as the underside 12 arranged. These are shown here as an example of a color filter layer. 41 as well as a masking layer 42 . This arrangement allows the glass or glass-ceramic element to be 1 can be divided into different areas. In area 5 is the visibility of an electro-optical display element 2 opposite the area 6 , in which the layer does not contain any scattering particles 3 between the underside 12 and the display element 2 is arranged, improved. In the area not described here, between the areas 5 and 6 The lying area is due to the masking layer. 42 No visibility whatsoever of an electro-optical display element 2 given. The masking layer 42It can be designed in such a way that letters, numbers, logos, graphic representations, etc., are left out, allowing a variety of possible patterns to be presented in the form of a luminous display or a luminous surface.

[0062] Furthermore, it shows Fig. 1b) a further embodiment of the glass or glass-ceramic element according to the invention 1 Here is between the underside 12 as well as the electro-optical display element not shown 2 The layer comprises the scattering particles and a silicon-containing binder. 3 arranged in the area 5 This determines the visibility of the display element. 2 opposite the area 6 improved. In the undesignated areas between the area 5 and the area 6 , in which the masking layer 42 directly onto the underside 12 of the glass or glass-ceramic element1 Due to the masking, there is no visibility of what was applied. Furthermore, the top side is also... 11 of the glass or glass-ceramic element 1 designated.

[0063] In Fig. 1c) is a further schematic and not to scale illustration of an embodiment of a glass or glass-ceramic element according to the invention. 1 to see, whereby the masking layer 4 a layer comprising the scattering particles and a silicon-containing binder 3 was applied. The areas are further described. 5 and 6 as well as the underside 12 and the top 11 of the glass or glass-ceramic article 1 .

[0064] Fig. 2a) shows a further schematic and not to scale representation of an embodiment of a glass or glass-ceramic article 1according to the present invention. The areas are designated here as follows: 5 , in which the visibility for the (not shown) electro-optical display element 2 opposite the area 6 has improved. In the areas 5 is a layer 3 , which includes scattering particles and a silicon-containing binder.

[0065] In Fig. Figure 2b) shows a further schematic and not to scale representation of an embodiment of the invention. The glass or glass-ceramic article 1 has a top side 11 as well as a subpage 12 on, whereby the underside 12 It is formed here with a textured surface. In that area 5 is between an electro-optical display element 2 (not shown) and the underside 12 a layer comprising scattering particles and a silicon-containing binder 3arranged. Furthermore, the layers are shown here. 42 , which have a masking function, as well as the layer 41 , which functions as a color filter. These layers are also located between the electro-optical display element. 2 and the underside 12 of the glass or glass-ceramic element 1 arranged in the area 5 is the visibility for the electro-optical display element 2 compared to the area 6 improved. In the area between the 5 and the area 6 arranged, here unnamed area in which the masking layer 42 Because of the masking effect of this layer, no electro-optical display element is visible.

[0066] Finally, it shows Fig.2c) another schematic and not to scale representation of a glass or glass-ceramic element 1 according to the present invention. In addition to the one described in Fig. 2b) the glass or glass-ceramic element shown 1 is the shift still here 43 arranged here as the so-called immersion layer, the structures of the underside 12 at least partially filled.

[0067] In Fig. Figure 3 is a schematic and not-to-scale representation of a glass or glass-ceramic element. 1 having a top 11 as well as a subpage 12 to be seen. Below the underside 12 is an electro-optical display element 2 trained, which here exemplifies various light sources 21 The electro-optical display element comprises these light sources, which are positioned at a distance d from each other.2 a distance to the underside 12 of the glass or glass-ceramic element 12 from a on, where this distance is the distance between the display element and the underside 31 the shift 3 This results in the following. The layer thickness is usually... 3 in the micrometer range and therefore so small that the distance between the underside is approximately 12 and the electro-optical indicator element a can be assumed, which is usually at least 2 orders of magnitude above the thickness of the layer 3 or the sum of the layer thicknesses between the underside 12 and the display element 2 The layer is arranged in layers. 3 is in that area 5 arranged in which improved visibility for an electro-optical display element 2 is given.

[0068] In Fig.Figure 4 is a representation of the normalized intensity of the light sources. 21 an electro-optical display element 2 for a backlit area of ​​a glass or glass-ceramic element 1 The curve labeled 7 shows the normalized intensity I of the light sources. 21 for a glass or glass-ceramic element according to the invention 1 , where the ratio of a to d is at least 1 The normalized intensity I is always at least 0.9 times the intensity I0, which occurs when viewed perpendicularly directly above the light source, exemplified here at positions 4, 5, 6, 7, 8, 9, and 10. The curve labeled 8, on the other hand, shows the fluctuations in intensity if the light sources are arranged in a different geometric configuration. 21 relative to the surface 31 is available.

[0069] Fig.Figure 5 shows a photographic representation of a backlit area of ​​a glass or glass-ceramic element according to the present invention. This photograph was taken at an angle of 80° to the surface normal, looking down onto the top surface. 11 of the glass or glass-ceramic element 1 The modification was carried out. The backlit area is still clearly visible even when viewed from the side.

[0070] Fig. Figure 6 further shows the photographic representations of two different glass or glass-ceramic elements. 1 In Fig. 6a) is a glass or glass-ceramic element 1 (not designated) to see which in the area 5 was coated. This is evident from the fact that the light sources 21 when viewed from above, they remain clearly recognizable as such (see the area marked as an example). 52 , which forms a kind of halo around the light source 21(represents). Between the two areas described here as examples 52 or between the two light wells, the distance l is defined, which is also labelled. Outside the areas 52 , of which only two are shown here, lies the area 51 The coating of the area, which comprises scattering particles, differs in its composition. 5 the Fig. 6a) and the Fig. 6b) by the proportion of scattering particles. For example, the diameter of the areas described here is 52 or halos of 4 mm. However, this value varies depending on the type of light source used.

[0071] In the lower photographic image of a glass or glass-ceramic element 1 This is a representation of a glass or glass-ceramic element. 1 with a scattering layer 3according to a preferred embodiment of the invention in the area with improved visibility for an electro-optical display element 5 Here too, the areas are 52 indicated, however, these can no longer be visually distinguished from the areas. 51 They can be distinguished. The entire area 5 It is therefore evenly illuminated.

[0072] To evaluate the light point resolution, the brightness values ​​can be taken from the photographic images of the light bars, which are shown as examples in Fig. Figure 6 is shown and can be evaluated. A suitable parameter is the ratio of minimum intensity to maximum intensity along the connecting line of the LEDs between the two outer LEDs, I. min / I max The corresponding values ​​are listed in the table below. Sample No. Scattering layer parameters Invisibility of the studs Light point resolution I Min / I Max pigment Portion LM additive Sieve Temp. 1 TiO2 10% 5% 140 200 0 0,88 2 TiO2 10% 5% 140 250 + 0,88 3 TiO2 15% 5% 140 200 0 0,98 4 TiO2 15% 5% 140 250 + 0,98 5 TiO2 20% 5% 140 200 0 0,99 6 TiO2 20% 5% 140 250 + 0,99 7 R320 10% 5% 140 200 + 0,89 8 R320 10% 5% 140 250 0 0,89 9 R320 15% 5% 140 200 + 0,95 10 R320 15% 5% 140 250 + 0,95 11 R320 20% 5% 140 200 + 0,99 12 R320 20% 5% 140 250 + 0,99 13 R320 20% 180 200 0 0,98 14 R320 20% 180 250 + 0,98 15 R320 20% 5% 140 200 + 0,98 16 R320 20% 5% 140 250 + 0,97 17 R320 20% 5% 140 200 + 0,98 18 R320 20% 5% 140 250 0 0,98

[0073] The "Pigment" column lists the pigments used, which are two different titanium dioxide variants. The percentage is given in wt.%. "LM" denotes a solvent that may be added to the liquid coating material and is also given in wt.%. The mesh size of the sieve is specified. The temperature is given in °C and indicates the curing temperature.

[0074] When the samples produced in this way are visually examined, it turns out that for ratios I min / I max of more than 0.95 the individual point light sources 21 no longer considered "visible", i.e., the "light wells" or areas 52 are no longer perceptible as such.

[0075] Furthermore, in Fig. 7. The phenomenon of so-called “optical wander” is described in more detail.

[0076] Fig. Figures 7a) and b) each show a glass or glass-ceramic element in a schematic and not to-scale representation. 1 , which in this case is smooth on both sides. The glass or glass-ceramic element 1 The upper side facing the two viewers B1 and B2 still shows 11 as well as the underside facing away from viewers B1 and B2 12 The thickness of the glass or glass-ceramic element 1 This has the value D.

[0077] In Fig. 7a), which is a glass or glass-ceramic element not according to the invention 1 shows, is at a distance h from the bottom. 12 of the glass or glass-ceramic element 1 a mask 9 arranged, however, such masking 9 , for example in the form of a aperture, is not necessarily required. Between the two masks 9 is the display element 2arranged, shown here by way of example as at least one point light source 21 comprehensive.

[0078] In general, without limiting oneself to the example of a display element shown here. 2 , which includes at least one point light source 21 The display element can also be designed as a display.

[0079] The glass or glass-ceramic element 1 It is backlit here, with the light coming from the display element. 2 which one is between the two masks 9 is arranged.

[0080] Depending on the viewing angle of the backlit glass ceramic, the location of the backlit area appears to "wander." The viewing angle α here refers to the angle between the viewing direction and the surface normal (viewing angle).

[0081] During the migration of the display element's location 2 The term "backlit area" here refers to the actual location of the display element O. t from the perceived location O w deviates, specifically by the deviation w α . O w is in Fig. 7a) only for viewer B2.

[0082] In Fig. 7a) If observer B1 views the glass ceramic at an angle α = 0°, the actual location O t of the display element 2 and the projection of the display element 2 on the glass or glass-ceramic element 1 , that is, the perceived location O w , thus coincide, i.e., the deviation w α For α = 0°, the value is 0. This applies to observer B2, who is viewing the glass or glass-ceramic element. 1 When viewed at an angle α ≠ 0°, the refraction of light at the glass or glass-ceramic element results in... 1This means that the actual location of the light source and the projection onto the glass ceramic no longer coincide. Rather, the actual location of the display element deviates from its apparent location by the deviation w. α This is calculated in the case of the in Fig. 7a) arrangement shown

[0083] In Fig. 7b), in which a glass or glass-ceramic element according to the invention 1 As shown, it is on its underside 12 a layer comprising scattering particles 3 in that area 5 arranged through this layer 3 The optical wander is reduced and the deviation w α This results for observer B2, who sees the glass or glass-ceramic element 1 Viewed from angle α, only to

[0084] The deviation w α , determined by the distance from O t and O w, which here in Fig. 7b) is also only designated for observer B2, is thus clearly determined here solely by the thickness of the glass ceramic and in contrast to the case in Fig. 7a) significantly reduced, as the distance between the display element or light source and the underside of the glass or glass-ceramic element 1 is no longer relevant. Reference symbol list 1 glass or glass-ceramic element 11 Top side of the glass or glass-ceramic element 12 Underside of the glass or glass-ceramic element 2 electro-optical display element 21 Light source in the electro-optical display element Layer comprising 3 scattering particles 31 Underside of the layer 3 4 more shifts 41st shift 4 , designed as a color filter layer 42 layers 4 , designed as a masking layer 43rd shift 4 , trained as an immersion layer 5 areas with improved visibility 51 area within area 5 , outside the light wells 52 52 area within area 5 , atrium 6 – Area with unchanged visibility 7, 8 Course of the normalized intensity I in a backlit area 9. Masking B1, B2 Viewer α Viewing angle w α deviation O t actual location of the light source / display element O w perceived location of the light source / display element h Distance between light source / display element and underside of the glass or glass-ceramic element D Thickness of the glass or glass-ceramic element QUOTES INCLUDED IN THE DESCRIPTION

[0085] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0086] DE 10259297 B4

[0007]

Claims

[1] Glass or glass-ceramic element with improved visibility for electro-optical display elements ( 1 ) in at least one area ( 5 ), having a top surface ( 11 ) and a subpage ( 12 ), where the top side ( 11 ) the side of the glass or glass-ceramic element ( 1 ) is designated which, in its use, is facing the user, and as a subpage ( 12 ) the side which is facing away from the user during use, as well as on the underside ( 12 ) at least in that area ( 5 ) with improved visibility for electro-optical display elements, at least one layer ( 3 ), which has a content of scattering particles between 0.1 and 25 wt.% and a silicon-based binder, wherein the transmission T b in that area ( 5 ) with improved visibility for electro-optical display elements between 15 and 30% of the transmission T uan uncoated area ( 6 ) of the glass or glass-ceramic element ( 1 ) amounts. [2] Glass or glass-ceramic element ( 1 ) according to claim 1, wherein the display location of a display element ( 2 ) when viewed at an angle α, (O w ), compared to the display location when viewed vertically, (O t ) a deviation w α shifts, which results from the following equation: where D is the thickness of the glass or glass-ceramic element ( 1 ) and n denotes the refractive power of the glass. [3] Glass or glass-ceramic element ( 1 ) according to one of claims 1 or 2, wherein the haze value in the range ( 5 ) is more than 95%, as determined by measurement with the Haze Guard Dual measuring device. [4] Glass or glass-ceramic element ( 1) according to one of claims 1 to 3, wherein the illumination intensity I normalized to the illumination intensity I0 of the display of an electro-optical display element ( 2 ) in the area ( 5 ) with improved visibility, at least 0.9 times the illuminance I0, which is perpendicular to the at least one light source ( 21 ) is present. [5] Glass or glass-ceramic element ( 1 ) according to any one of claims 2 to 4, wherein the at least one light source ( 21 ) is designed as a point light source. [6] Glass or glass-ceramic element ( 1 ) according to any one of claims 2 to 5, wherein the electro-optical display element ( 2 ) at least two point light sources ( 21 ) exhibits, which are arranged a distance a from each other. [7] Glass or glass-ceramic element ( 1) according to claim 7, wherein the ratio of the distance a between the glass or glass-ceramic element ( 1 ) and the at least two point light sources ( 21 ) to the distance d between the at least two point-like light sources ( 21 ) takes on a value of 1 or more. [8] Glass or glass-ceramic element ( 1 ) according to any one of claims 1 to 7, wherein the scattering particles have a mean primary grain size between 200 and 800 nm and a refractive index greater than 1.6 at a wavelength of 560 nm. [9] Glass or glass-ceramic element ( 1 ) according to any one of claims 1 to 8, wherein the scattering particles comprise TiO2, ZrO2, ZnO, ZnS, PbCO3, BaSO4 and / or mixtures thereof, for example lithopones. [10] Glass or glass-ceramic element ( 1 ) according to any one of claims 1 to 9, wherein the silicon-containing binder comprises a silicone resin, preferably a polyester-modified silicone resin. [11] Glass or glass-ceramic element ( 1 ) according to any one of claims 1 to 10, wherein the layer ( 3 ) comprises a chromophore or a mixture of chromophores, for example a luminescent pigment and / or a luminescent dye. [12] Glass or glass-ceramic element ( 1 ) according to one of claims 1 to 11, wherein between the display element ( 2 ) and the glass or glass-ceramic element ( 1 ) at least one more layer ( 4 , 41 , 42 , 43 ) is arranged. [13] Glass or glass-ceramic element ( 1 ) according to any one of claims 1 to 12, wherein the thickness of the layer ( 3 ) between 1 and 50 µm, preferably between 4 and 10 µm. [14] Method for producing a glass or glass-ceramic element ( 1 ) with improved visibility for electro-optical display elements ( 2 ), encompassing the following steps: a. Provision of a glass or glass-ceramic element ( 1 ) with a top surface ( 11 ) and a subpage ( 12 ), b. Providing a liquid coating material comprising at least a silicon-based binder, a solvent and spreading particles, c. Applying the liquid coating material to at least one area ( 5 ) the underside ( 11 ) of the glass or glass-ceramic element ( 1 ) d. Curing of the coating material, resulting in cross-linking of the silicon-containing binder. [15] Method according to claim 14, wherein the application is carried out by means of rollers, casting, squeegees or by means of a printing process, preferably by means of screen printing or inkjet printing. [16] Method according to claim 15, wherein the coating material is applied by a screen printing process and the application is carried out using a screen with a thread count between 200 and 100 threads per centimeter, preferably with a thread count of 180, 140 or 120 threads per centimeter. [17] Method according to any one of claims 14 to 16, wherein the curing is carried out thermally at a temperature between 375°C and 150°C for a duration of at least 10 minutes up to a maximum of 2 hours, preferably between 275°C and 180°C and particularly preferably 250°C for a duration of 30 minutes up to one hour. [18] Method according to any one of claims 14 to 17, wherein the at least one silicon-containing coating agent is formed as a silicone resin, preferably as a condensation-curing silicone resin and most preferably as a polyester-modified condensation-curing silicone resin. [19] Method according to claim 18, wherein the silicone resin has functional groups. [20] Method according to any one of claims 14 to 19, wherein the coating agent comprises at least one surface-active additive, preferably a surface-active deaerating and / or defoaming additive. [21] Method according to claim 20, wherein the total content of additives, based on the mass of the coating material, is between 0.5 and 6 wt.%. [22] Method according to any one of claims 14 to 21, wherein the coating agent comprises a hydrolysate of an organic compound of a metal and / or a semimetal, preferably a hydrolysate of an organosilicon compound. [23] Glass or glass-ceramic element ( 1 ), manufactured or manufactureable by a process according to any one of claims 14 to 22.

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