Vehicle glazing with a light-diffusing print

Abstract

The invention relates to a vehicle glazing (3) with a light-guiding glass pane (8) having a printed pattern (11), with light coupling from a lighting device (4) into the glass pane (8) via an edge region (5) of the glass pane (8) and with light coupling of the coupled light from the glass pane (8) by means of the printed pattern (11) of the glass pane (8), wherein the printed pattern (11) is formed as a light-diffusing structure from ink printed on the glass pane (8) and wherein a polymeric top layer (10) covers the light-diffusing structure, and with a low-E coating (19) of the glass pane (8). According to the invention, it is provided that the refractive index n G of the glass pane (8), the refractive index n P the printing (11) and the refractive index n D the top layer (10) in the ratio n G ≥ n D and n P ≥ n D stand.

Description

[0001] The invention relates to a vehicle glazing with a light-conducting glass pane having a print, with a light coupling of light from a lighting device via an edge region of the glass pane into the glass pane and with a light coupling of the coupled light out of the glass pane by means of the print on the glass pane, wherein the print is formed as a light-scattering structure of ink printed on the glass pane and wherein a polymeric cover layer covers the cured ink, and with a low-E coating on the glass pane.

[0002] EP 3 702 217 A1 discloses vehicle glazing with a printed, light-conducting glass pane. The printing is done with individual ink drops that are spaced apart from each other and allow visibility through the printed glass pane. However, such printing can cause optical distortions for a viewer viewing a scene through the printed glass pane due to the lens effect of the printed structures. Such optical distortions can occur, for example, due to different refractive indices of the printing and the polymeric cover layer.

[0003] To reduce heat radiation from a vehicle, low-emission coatings (low-E coatings) that reflect heat radiation are used on the inside of the window facing the vehicle interior. Due to non-color-neutral internal reflection at the interface between the light-conducting glass and the low-E coating, the low-E coating on the glass pane leads to a lateral color drift of the light totally reflected in the light-conducting glass pane. For example, a greater attenuation of the red light component leads to an increasingly turquoise color of the white light coupled into the glass pane.

[0004] The invention is based on the object of creating a vehicle glazing as mentioned above which is improved with regard to its optical properties.

[0005] The object is achieved according to the invention in the vehicle glazing mentioned at the outset in that the refractive index n Gthe glass pane, the refractive index n P the printing and the refractive index n D the top layer in the ratio n G ≥ n D and n P ≥ n D .

[0006] Advantageous embodiments of the invention are specified in the dependent claims.

[0007] The color drift of the light totally reflected in the light-conducting glass pane depends on the angle of reflection in such a way that light components reflected in the glass pane at shallower angles exhibit greater color drift. With the inventive determination of the ratio n G ≥ n P > n D the refractive indices n G , n P and n DThis ensures that those light components reflected at shallower angles in the glass pane, which exhibit greater color drift, are not coupled into the printed light-scattering structure formed by the ink droplets. This at least reduces color drift. Optical distortions for the viewer can also be reduced or largely eliminated.

[0008] In one embodiment, it is provided that the ratio of n G and n P applies: n P ≥ n G . Based on this ratio, the intensity of the light output is optimized or maximized, since the light-conducting glass pane receives light with increasing refractive index n P in relation to the refractive index n G more light is coupled into the printing and is coupled out via the printing.

[0009] Furthermore, the use of conventional clear soda-lime silicate glass typically results in a color drift toward green due to iron oxide absorption. This color drift can be largely eliminated by using low-iron glass, such as glass with a low iron oxide content of < 0.05% and especially < 0.02%.

[0010] In one embodiment, the values ​​of the refractive indices in the visible range, for example for light of 589.33 nm, are: n G >= 1.5, in particular in a range of 1.5 to 1.58 n D <= 1.49 and in particular in a range of 1.48 to 1.49; and n P > 1.48, and in particular in a range from 1.48 to 1.9, preferably in a range from 1.48 to 1.7; and in particular n G = 1.51 to 1.52, n D = 1.48 to 1.49 and n P = 1.51 to 1.53.

[0011] Preferred refractive indices (at wavelength 589.33 nm) are, for example, for glass material n G =1.505, for PVB (polyvinyl butyral) as top layer n D =1.482. The refractive index of the light-scattering structure is preferably in the range n P = 1.482 to 1.505.

[0012] In the glass pane, for example, light is guided at shallow angles to the interface. Light with an angle of incidence (measured to the interface) smaller than the critical angle of total internal reflection α D = 90°-arcsin(n D / n G) is totally reflected and guided, while light at a larger angle penetrates the top layer, is absorbed there, and is no longer transmitted through the glass. The critical angle is therefore the angle between the interface and the angle of incidence of the light. A shallow angle for light is understood here as an angle sufficient to achieve total internal reflection and thus less than or equal to the critical angle of total internal reflection.

[0013] The cover layer consists in particular of a thermoplastic material such as PVB (polyvinyl butyral), TPU (thermoplastic polyurethane) or EVA (ethylene-vinyl acetate) and can preferably be dark-tinted.

[0014] Preferred refractive indices (at wavelength 589.33 nm) are, for example: n G =1.505, for PVB as top layer n D =1.482. The refractive index of the light-scattering structure is preferably in the range n P = 1.482 .. 1.505.

[0015] The critical angle of total reflection (measured at the interface) at the interface between the glass pane and the printed structure is α D = 90°-arcsin(n D / n G ). Light with an angle greater than α D enters the printed structure in the area where the glass pane is covered by the printed structure. The penetrating portion of the light guided in the glass pane is thus 1-(α P / α D ). The intensity of the scattered light is given by n D and n G determined by the refractive index of the printed structure.

[0016] A printed structure is a structure applied to the surface of the glass pane. The structure can be applied directly or indirectly to the surface of the glass pane. In direct application, a structure is applied to the surface of the glass pane, in particular by a printing process. Structural elements in the form of an ink are arranged on the surface of the glass pane in such a way that they form, in particular, a light-scattering, light-refracting and / or light-diffracting structure. In direct application, ink droplets are preferably applied to the surface of the glass pane. The ink droplets can be in a solid or liquid state. In indirect application, structural elements are applied to a carrier material. The structural elements are preferably formed analogously to the previously described structural elements in direct application.The carrier material is applied to the surface of the glass pane, with the structural elements applied to the carrier material being arranged on the surface of the glass pane. In one embodiment, the carrier material is removed. The structure applied directly to the surface of the glass pane and / or the structure applied to the carrier material is produced, for example, by means of preferably digital printing such as laser printing or inkjet printing, intaglio printing, and / or screen printing.

[0017] Printed structures with rounded surfaces that are not parallel to the surface of the glass create distortion when viewed through.

[0018] The distortion of a printed structure or ink droplet, which can be described as a plano-convex lens, for example, using the local radius of curvature R, can be estimated using the lens grinder formula: D=1 / f=(nP / nD) / R, where R is the local radius of curvature, the local radius of the interface to the cover layer of the printed structure or the ink droplet.

[0019] While with decreasing refractive index n P in the range between the refractive index n G and the refractive index n D If the distortion or refractive power decreases linearly, the intensity of the light scattering decreases more than linearly. A reduction in intensity to, for example, about 50% results in an improvement in refractive power of only about 25%. By balancing the desired intensity against tolerable optical distortions, a refractive index n is thus determined. P the printed structure.

[0020] According to a preferred embodiment, the material of the printed structure is chosen so that its refractive index n P in the area n P > (n G + n D) / 2. Thus, the intensity of light scattering is optimized by scattering particles introduced into the printed structure.

[0021] In a further preferred embodiment, the refractive index n P the light-scattering structure has a value of n P < (n G + n D ) / 2. The optical distortions are optimized so that only a small amount of distortion is observed.

[0022] According to a preferred embodiment, the ink contains scattering particles having the refractive index n P of the print or the light-scattering structure or the ink droplets, and the refractive index can be advantageously adjusted via their proportion in the ink. The volume fraction of the scattering particles and / or the material of the scattering particles is important for the refractive index to be adjusted, n PThe printing or ink droplets or the light-scattering structure are selected. The volume fraction of scattering particles in the ink is, for example, 5% to 50%. A volume fraction of 30% to 40% of TiO2 particles has proven advantageous.

[0023] The transparent ink consists of a UV-curing acrylic resin with particles of oxides or nitrides, such as TiO2 or Al2O3, distributed throughout. Common products contain, for example, 2-phenoxyethyl acrylate or isobornyl acrylate as a base.

[0024] Since acrylic resins typically have poor adhesion to the PVB of the top layer, it may be advantageous to add adhesion promoters to the resin to improve adhesion to the PVB.

[0025] The printed structure may consist of a plurality of individual, in particular small, discrete ink drops which do not appear to be soluble to the eye and are in particular spaced apart from one another.

[0026] The ink droplets are preferably printed in a lens-shaped or semi-ellipsoidal shape. The ink has a viscosity such that, when applied to the glass pane, particularly using digital printing, the ink forms a droplet of this shape on the glass pane. The shape of the semi-ellipsoid is further determined by the speed of the ink upon impact with the glass pane and by the curing speed of the ink or ink droplet upon drying. These parameters are defined such that the ink droplet has the desired shape after drying and curing. The semi-ellipsoid has a diameter of its base and a height that are in a ratio of, for example, 0.5 to 1.5.A flank angle of the ink drop, which is defined as the angle between a perpendicular to the glass plate at the edge of the ink drop and a tangent emanating from the glass plate at the circumference of the semi-ellipsoid, is preferably about 5° to 10° at the base of the semi-ellipsoid or the ink drop and preferably about 15° to 30° at half the height of the semi-ellipsoid or the ink drop.

[0027] The shape of the semi-ellipsoid represents an approximation to the real shape of the ink drop for the purpose of describing it. Small deviations of the ink drop from this shape can therefore be neglected for the description of the ink drop.

[0028] Furthermore, the glass pane can be provided with a second outer glass pane or outer pane, which is laminated to the side of the glass pane bearing the printing by means of the cover layer. This creates a laminated glass pane.

[0029] The outer glass pane or outer pane of a laminated glass pane can be either transparent or opaque. Light transmission is generally not required if the vehicle glazing is intended to provide ambient lighting. Thus, the vehicle glazing can also be transparent or opaque. Preferred embodiments have light transmissions (TL according to ISO 11664) of <20%, particularly preferably <10%.

[0030] The glass pane can be quartz glass, single-pane float glass, tempered glass (ESG) or heat-strengthened glass (TVG), for example, and it can also be made of a plastic such as polycarbonate.

[0031] A lighting device or at least one light source of such a lighting device for introducing light is preferably arranged on one of two lateral and opposite edges or edge regions of the glass pane or of a laminated glass pane comprising the glass pane, wherein the lateral edge refers to a left and a right side edge of the substantially rectangular glass pane or laminated glass pane arranged on a vehicle roof. The light from the light source can be coupled in via the side edge or via a side surface on the side edge of the glass pane or via an edge strip on an inner or underside main surface of the glass pane, e.g., by means of optical prisms arranged on the edge strip (as disclosed in WO 2023 / 031460 A1) or other optical light-guiding devices or light-coupling devices.

[0032] Furthermore, a generally vertical light coupling from below can be provided via the inner or underside main surface of the glass pane. In this case, an optical device is provided, for example, a diffuser layer or a diffuser element, which is arranged opposite the light coupling or a light source, for example on an inner main surface of a second glass pane. The optical device scatters or deflects coupled-in light such that the coupled-in light is predominantly deflected at an angle that is guided in the second glass pane by total internal reflection.

[0033] The invention will be explained in more detail below using exemplary embodiments of a vehicle glazing according to the invention with reference to the drawing. It shows: Fig. 1 shows a perspective view of a vehicle with a vehicle roof having vehicle glazing; Fig. 2 shows a schematic sectional view of a light-conducting glass pane of the vehicle glazing with light reflection in the glass pane and light scattering on a print on the glass pane covered by a cover layer; Fig. 3 in a sectional view in schematic representation an enlarged section of the light-conducting glass pane with representation of the light reflection and the light scattering on the printing of the glass pane; Fig. 4 in a sectional view in schematic representation the light-conducting glass pane with reflected light conduction and with light scattering at the printing of the glass pane; and Fig. 5 shows a schematic sectional view of another embodiment of the vehicle glazing.

[0034] A vehicle such as a passenger car comprises a vehicle roof 1 ( Fig. 1) with a roof opening 2, in which a vehicle glazing 3 is arranged, which, for example, is fixedly arranged in the roof opening 2 or is formed as a cover that is movably mounted in the roof opening 2 by means of a bearing device and adjustable between a closed position and ventilation or open positions in a manner known per se. The vehicle glazing 3 can also be a fixed part or section of a roof module or panoramic roof. A lighting device 4 is arranged on each of the two opposite lateral edge regions 5 of the vehicle glazing 3 and extends on the inside 6 of the pane, preferably along a respective side edge 7 of the vehicle glazing 3.

[0035] The vehicle glazing 3 comprises, in particular, a laminated glass pane with a glass pane 8 as the inner pane, an outer pane 9, and a polymeric cover layer 10 as a connecting layer, which connects the glass pane 8 to the outer pane 9 and contains, for example, a laminate layer, laminate film, or hot-melt adhesive film, in particular made of PVB, TPU, or EVA. The outer pane 9 is, for example, a tinted glass pane, which can be both transparent and non-transparent. The inner glass pane 8 is, in particular, a transparent and light-conducting glass pane or clear glass pane, preferably made of low-iron glass, which forms a light-conducting layer for coupled-in light. The cover layer 10 covers a print 11 arranged on an inner main surface 12 of the glass pane 8. The print 11 is produced with ink, which is preferably sprayed or printed onto the glass pane 8 using a digital printing process.The individual ink drops 13 formed with the ink form a light-scattering structure of the print 11.

[0036] The lighting device 4 (in Fig. 2 schematically shown as a light source) contains, for example, a plurality of LEDs or RGB LEDs as light sources, which are arranged along the side edge 7 of the glass pane 8 and whose light is coupled into the glass pane 8, for example, via an edge-side side surface 14 of the glass pane 8. Light rays 15 of the coupled-in light are reflected in the glass pane 8 at an inner boundary surface 16 and at an outer boundary surface 17. The inner boundary surface 16 corresponds to the inner main surface 12 covered by the cover layer 10. The outer boundary surface 17 corresponds to an outer or lower main surface 18 of the glass pane 8, which faces a vehicle interior.

[0037] The glass pane 8 has a low-emission coating or low-E coating 19 on its outer or lower main surface 18. The low-E coating 19 reduces the solar energy radiated into the vehicle and the thermal radiation emitted by the vehicle interior, thereby reducing the sensation of cold among vehicle occupants.

[0038] The glass pane 8 has a refractive index n G of preferably 1.505. The print 11 or the scattering structure or the ink drop 13 has a refractive index n P from 1.485 to 1.505 and in particular 1.50. The cover layer 10 has a refractive index n D of 1.485 in particular.

[0039] Light rays 15 that strike the interfaces 16 and 17 at angles α that are smaller than the critical angle of total internal reflection are totally reflected in the glass pane 8 and do not exit the glass pane 8 via the interfaces 16 and 18. The critical angle (measured between the light beam and the interface) of total internal reflection is determined by α D = 900-arcsin(n D / n G ). For n D = 1.485 and n G = 1.505 the critical angle α D = 9.35°. Thus, at this critical angle, only light rays 15 oriented very flatly relative to the interface 16 are totally reflected at the interface 16 of the glass pane 8 facing the cover layer 10. The glass pane 8 therefore acts as a light guide for such flat light rays.

[0040] Light rays 15 that impinge on an ink droplet 13 of the light-scattering structure of the print 11 at the inner interface 16 enter the ink droplet 13 at corresponding angles and refractive indices and are reflected at the interface between the ink droplet 13 and the cover layer 10 covering the ink droplet 13. They are coupled out as scattered light via the lower main surface 18 toward the vehicle interior. This creates ambient lighting.

[0041] The printing 11 on the glass pane 8 is carried out with a transparent ink using inkjet digital printing. The preferably UV-curing ink contains a mixture of, for example, monomers, oligomers, photoinitiators, additives, and scattering particles. The printer sprays the ink onto the glass pane 8 in very small, spaced-apart droplets. Preferred resolutions for this digital printing are in the range of 100 dpi to 1000 dpi (dots per inch), and particularly preferably in the range of 360 dpi to 450 dpi.

[0042] In one embodiment, adjacent droplets flow into each other after printing and form a common printing surface on the glass pane 8. These adjacent droplets are therefore no longer distinguishable separately or individually. This behavior depends on the surface tensions of the ink and the glass pane.

[0043] When the ink is printed onto the glass pane 8, the resulting ink droplets 13 are irradiated with UV light to trigger the polymerization of the ink and cure the ink droplets 13. The UV light source is typically a special lamp that emits UV light at a specific wavelength tailored to the ink to achieve optimal curing. Curing can occur very quickly, typically in just a few seconds.

[0044] The scattering structures or ink droplets 13 can be printed over the entire printing area, e.g., in a uniform grid pattern. The ink droplets 13 can also be printed according to a desired design in such a way that they are printed in the form of a pattern, e.g., with different sizes of the ink droplets 13 and different spacing between the ink droplets. The ink droplets 13 can also be printed in different thicknesses or heights, as well as in different sizes or diameters.

[0045] The sizes or diameters of the scattering structures or the ink drops 13 are preferably in the range from 0.035 mm and in particular in the range from 0.035 mm to 0.15 mm.

[0046] The refractive index n P of the scattering structures or the ink drops 13 results from a mixture of the refractive index of the matrix of the ink and the refractive index of the scattering particles contained in the ink.

[0047] By choosing the material of the matrix of the ink with the refractive index n M and the scattering particle with the refractive index n B and the volume fraction of the scattering particles in the ink, the refractive index n P of the scattering structures in the range between n M and n B set.

[0048] The ink used in UV-curable inkjet printing contains an ink mixture of monomers, oligomers, photoinitiators, and additives. These components create a liquid ink that is printed onto a substrate such as glass and rapidly cured with UV light. The monomers and oligomers are the essential components of the ink and form the majority of the ink's physical properties. Photoinitiators are added to the ink to initiate the curing process upon exposure to UV light. Additives can be added to improve ink adhesion, print quality, and other properties. Some common materials used for UV-curable inkjet inks include acrylates, epoxies, urethanes, and polyesters.The refractive index of UV-curable inkjet printing inks varies depending on the composition of the ink and the materials used and is generally in the range of approximately 1.40 to 1.60.

[0049] To achieve light scattering by the ink droplets, scattering particles are added to the ink mixture. These particles have a greater refractive index difference than the surrounding matrix or liquid of the ink. These scattering particles can be made of various materials. Some examples of scattering particles and their refractive indices are: silicate (n = 1.50 to 1.54), titanium dioxide (n = 2.35 to 2.55), barium sulfate (n = approximately 1.64), and calcium carbonate (n = 1.48 to 1.66). By adding scattering particles that scatter in the visible wavelength range, the light is scattered in the ink droplets, creating diffuse ambient lighting. The size, shape, and distribution of the scattering particles influence the intensity and type of light scattering. It should be noted that an increased concentration of scattering particles can increase the viscosity of the ink and impair print quality.

[0050] The dielectric constant of the scattering structure can be calculated, for example, according to the Maxwell-Garnett theory from the dielectric constants of the matrix ε m and the inclusions ε i and the volume fraction δ i of the inclusions: εeff=εm2δi(εi−εm)+εi+2εm2εm+εi−δi(εi−εm)

[0051] For non-magnetic materials, the dielectric constant is equal to the square of the refractive index.

[0052] For example, for a matrix made of acrylate-based UV resin with n = 1.4, ε = 1.96 and with the addition of TiO2 particles with TiO2 n = 2.6, ε = 6.76, depending on their volume fraction, a refractive index n P the printing or ink can be adjusted from 1.4 to 2.6.

[0053] In one embodiment, the edge-side light coupling can be designed such that light coupling takes place within the vehicle glazing 3, for example in the case of a laminated glass pane by means of a lighting device 4 arranged within the laminated glass pane, and / or via an arrangement of the lighting device 4 at one of the boundary surfaces 16, 17.

[0054] The light guided in the light-guiding glass pane 8 is - as explained above - limited by the critical angle α of total reflection. A beam of the incident light L1 ( Fig. 3) is totally reflected and continues in the glass pane 8 as light beam L2 if it is flatter than the critical angle α and it penetrates into the cover layer 10 as light beam L3 if it is incident more steeply, ie with an angle α that is greater than the critical angle.

[0055] The refractive index n Pof the scattering structure or ink drop 13 determined together with the refractive index n G the glass pane 8, which portions of the transmitted light L2 can penetrate into the scattering structure or into the ink drop 13 as light beam L4 and which portions are totally reflected as light beam L5 at the interface 16.

[0056] The angles of incidence of the bundle of guided light L2 are according to α D = 90°-arcsin(n D / n G ) upwards. At the same time, only light with an angle of incidence of at least α P = 90°-arcsin(n P / n G ).

[0057] In order to couple light into the ink drop 13, the refractive index n P of the ink drop 13 must be greater than the refractive index n D the top layer (n P > n D ).

[0058] About the refractive index n PYou can also set the angle range between α P and α max the light beam L4 enters the ink drop 13. At a flat angle of incidence in the range 0° to α P it is totally reflected as light beam L5. The light beam L5 is therefore not coupled out of the glass pane 8.

[0059] The light guided in the glass pane 8 (see Fig. 4) is reflected at the interface 16 to the cover layer 10 and at the interface 17 to the low-E layer 19. On its way to the ink droplets 13, the light is reflected multiple times. With each reflection at the low-E layer 19, the light is reflected depending on the angle of incidence and the wavelength. Due to color-inhomogeneous reflection at the low-E layer 19, color shifts occur, which become more pronounced with each additional reflection at the low-E layer 19. For example, if an RGB LED of the lighting device 4 emits white light as a combination of the colors red, green, and blue, and less red than green or blue is reflected during the reflections, then when the light is coupled out at the ink droplets 13, it is not white light but turquoise light that is scattered and coupled out. Such color shifts should at least be reduced or completely avoided.

[0060] Experimental results and an optical simulation of internal reflection at the low-E layer 19 show that the inhomogeneity in spectral reflection increases significantly with shallower angles of incidence. It is therefore advantageous not to couple incident light into the printed structure at shallow angles of incidence, e.g., < 3°.

[0061] According to the invention, the refractive index n P The ink droplet 13 is adjusted via the volume fraction and the material of the scattering particles such that only light L4 enters the ink droplet 13 at larger reflection angles. Light impinging on the interface at shallow angles is blocked out, so that the color drift is at least reduced.

[0062] The greater the proportion of light coupled into the ink droplets 13, the brighter the ink droplets 13 or the light-scattering structure glows. The dependence of the intensity of the light coupling on the refractive index nP of the scattering structure or the ink drops 13 shows that it is advantageous to couple in as much light as possible. The ratio of the coupled light L4 to the uncoupled light L5 is determined by the refractive indices n P and n D It turns out that for n P >= n G maximum light coupling occurs and for n P = n D no light is coupled in.

[0063] For a high intensity of ambient lighting, it is therefore advantageous to have a refractive index n D the cover layer 10 large refractive index n P the ink drops 13 or the print 11 (n P > n D ).

[0064] Thus, a balance between high intensity and reduced color drift leads, according to the invention, to a determination of the refractive index n Pthe scattering structure or the ink drops 13 of the print 11 between the refractive index n G the glass pane and the refractive index n D the top layer 10.

[0065] According to a further embodiment ( Fig. 5) a modified structure in which the outer pane 9 has an IR-reflecting coating 21 on its inner main surface 20 and a black print 22 in the region of the side edge 7. The black print 22 conceals the lighting device 4 arranged there at the edge region and blocks unwanted light from the lighting device 4. The intermediate layer between the outer pane 9 and the inner glass pane 8 comprises, in addition to the cover layer 10, a laminating layer 23 which is connected to the outer pane 9 and is made of, for example, dark PVB. Furthermore, a switchable film 24 (e.g., PDLC (Polymer Dispersed Liquid Crystal)) is embedded between the cover layer 10 and the laminating layer 23. A frame 27, for example, made of PVB or TPU, surrounds the film 24 to compensate for any thickness difference at the edge of the switchable film 24. The switchable foil 24 is supplied with power via a contact 25.The contact 25 is connected to a power supply (not shown) via a contact area (not shown).

[0066] The light is coupled in from a light source, such as at least one LED or RGB LED of the lighting device 4, via an optical prism 26, which is bonded to the lower or outer main surface 18 of the glass pane 8 in an area exposed to the low-E layer. The light is coupled in, for example, according to the method known from WO 2023 031 460 A1.

[0067] At least one of the cover layer 10, the laminating layer 23 or the switchable film 24 may have a low light transmission in order to obtain an overall transmittance TL of < 20% or < 10%.

[0068] Instead of or in addition to the prism 26 shown here, a different type of light coupling into the light-guiding glass pane 8 can be selected, for example irradiation of light from a light source of a lighting device, for example a top LED, directed into the light-guiding glass pane and the use of scattering units in combination with the light source, whereby the irradiated light can be reflected and / or refracted into the glass pane in such a way as to guide the light by means of total internal reflection within the light-guiding glass pane. A top LED is characterized in that it emits light essentially perpendicular to a fastening device, for example a circuit board, of the LED, ie predominantly with a radiation cone of less than 125°, in particular less than 90°, preferably less than 60°.

[0069] The edge area 5 of the glass pane 8, through which the light is coupled, thus comprises the outer side edge 7 as well as an edge strip 28 (in Fig. 5) in the region of the lower main surface 18 of the glass pane 8. The edge strip 28 expediently has a width in the range of, for example, 0.5 cm to 10 cm. The width depends, for example, on the design of the glass pane or the laminated glass pane in the region of its side edge or edge area.

[0070] In principle, the printed light-conducting glass pane 8 is intended for use in both transparent and non-transparent vehicle glazing with ambient lighting. List of reference symbols 1 vehicle roof 2 roof opening 3 Vehicle glazing 4 Lighting device 5 Marginal area 6 Inside of the pane 7 Page margin 8 glass pane 9 Outer pane 10 Top layer 11 Printing 12 inner main surface 13 drops of ink 14 side surface 15 rays of light 16 inner interface 17 outer interface 18 lower main surface 19 Low-E layer 20 main area 21 Coating 22 Black printing 23 Laminating layer 24 switchable foil 25 Contacting 26 Prism 27 frames 28 verge strips QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 702 217 A1

[0002] WO 2023 / 031460 A1 [0031, 0066]

Claims

[1] Vehicle glazing (3) with a light-guiding glass pane (8) having a print (11), with light coupling from a lighting device (4) via an edge area (5) of the glass pane (8) into the glass pane (8) and with light coupling of the coupled light from the glass pane (8) by means of the printing (11) of the glass pane (8), wherein the printing (11) is formed as a light-scattering structure from ink printed on the glass plate (8) and wherein a polymeric cover layer (10) covers the light-scattering structure, and with a low-E coating (19) on the glass pane (8), characterized by , that the refractive index n G of the glass pane (8), the refractive index n P the printing (11) and the refractive index n D the top layer (10) in the ratio n G ≥ n D and n P ≥ n D stand. [2] Vehicle glazing (3) according to claim 1, characterized by , that the refractive indices measured at 589.33 nm are: n G ≥1.5, n D ≤ 1.49 and n P >1.48, especially n G >1.5 and n D ≤ 1.

49. [3] Vehicle glazing (3) according to claim 1 or 2, characterized by that the ink contains scattering particles which change the refractive index n P the printing (11) or the light-scattering structure determine, and that the volume fraction of the scattering particles for the refractive index to be set n P the printing (11) or the light-scattering structure is chosen, and that the volume fraction of the scattering particles is greater than 20% and preferably in the range of 20% to 50%. [4] Vehicle glazing (3) according to one of claims 1 to 3, characterized by, that the light-scattering structure is formed from individual ink droplets (13) which are in particular spaced apart from each other. [5] Vehicle glazing (3) according to claim 4, characterized by , that the individual ink droplets (13) have a mean diameter in the range of 0.05 mm to 0.1 mm. [6] Vehicle glazing (3) according to claim 4 or 5, characterized by , that the ink drops (13) are printed in a lenticular or semi-ellipsoidal shape. [7] Vehicle glazing (3) according to any one of claims 1 to 6, characterized by , that the glass pane (8) together with a second outer glass pane (9), which is laminated on the side of the glass pane (8) having the printing (11) by means of the top layer (10), provides a laminated glass pane. [8] Vehicle glazing (3) according to any one of claims 1 to 7, characterized by, that the glass pane (8) is made of a low-iron glass with an iron oxide content of < 0.05% and preferably < 0.02%. [9] Vehicle glazing (3) according to any one of claims 1 to 8, characterized by , that the intensity of the light coupled out at the light-scattering structure is optimized by adjusting the refractive index of the light-scattering structure according to n P > (n G + n D ) / 2 is set. [10] Vehicle glazing (3) according to any one of claims 1 to 9, characterized by , that optical distortions at the light-scattering structure in the vehicle glazing (3) are optimized by adjusting the refractive index of the light-scattering structure according to n P < (n G + n D ) / 2 is set.

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