Glazing with luminous coating and method for producing a glazing having a luminous coating

Description

The invention further relates to a glazing comprising a first layer (A) and a luminous coating. In a further aspect of the invention a glazing comprising a composite structure comprising a first layer (A), a second layer (B), and an interlayer (C) is provided, wherein at least the first layer (A) is an optically transparent layer produced in a float glass process having an air-side and a tin- side, and wherein the interlayer (C) is sandwiched between the first layer (A) and the second layer (B) and is arranged parallel to the first layer (A) and the second layer (B). Still further, a process for producing such a glazing is provided.

Laminated safety glass, comprising sheets of glass and plastic, is used in areas where structur- al integrity after fracture is highly desired or required for safety reasons, especially but not exclusive in the fields of architectural glazing or automotive glazing.

Toughened glass is treated such that the glass, when broken, crumbles into small granular chunks instead of splintering into jagged shards. Toughened glass is used in a variety of de- manding applications, such as architectural glazing or automotive glazing.

The surface of laminated safety glass or toughened glass may be used for these purposes in illuminated form or in not illuminated form, where the illumination may be produced by suitable light sources. It is possible that the complete surface is illuminated, but it is also possible to apply pattern onto the surface. It is further possible to use different light sources, whereby for example colored or blocked lighting effects are produced. The surfaces may be used for example in buildings, furniture, cars, trains, planes and ships as well as in facades, skylights, glass roofs, stair treads, glass bridges, canopies and railings. US 2015/308659 A1 concerns a glazing unit which includes sheets of glass and of plastic laminated between the glass sheets, and luminophores, wherein the glazing unit includes at least three glass sheets and at least two plastic films inserted in alternation between the glass sheets. The selection of at least three glass sheets associated with at least two intermediate films of plastic allows a three-dimensional image to be obtained.

US 2013/0252001 A1 concerns a laminated glazing for information display comprising an assembly of at least two transparent sheets of inorganic glass or of a strong organic material, joined together by an interlayer of a thermoformable material or by multilayer foils incorporating such interlayers, whereby said glazing being characterized in that a luminophore material of the hydroxyterephthalate type, combined with an antioxidant additive, is added into said interlayer. Further, in US 2013/0252001 A1 a device for displaying an image on transparent glazing is disclosed, comprising a laminated glazing as mentioned before and a source generating concentrated UV radiation of the laser type. DE 10 2005 061 885 A1 concerns a glass element being part of a facade of a building with a long afterglow effect based on an element with a long afterglow effect with inorganic long afterglow pigments in a matrix, whereby the long afterglow element is graphically designed and ap- plied to the glass element by screen printing or transfer technique, whereby the glass element is formed from at least two glass elements together with a carrier element, and the at least two glass elements form a laminated safety glass.

The glazing or lighting elements known in the prior art suffer from the problem that, when illumi- nated, glass sheets larger than 50 cm in one direction usually exhibit inhomogeneous color and light intensity due to light absorption and greenish color of glass sheets. Further, undesired light scattering in the glazing of known lighting elements is observed when the glazing comprises glass sheets produced in a float glass process. It is an object of the present invention over the prior art to provide an improved glazing which may be used in a lighting unit and which allows distribution of light with desired light color and light intensity distribution while avoiding undesired scattering of light.

A glazing comprising a first layer (A) is provided. The first layer (A) is an optically transparent layer produced in a float glass process having an air-side and a tin-side, wherein a luminous coating is applied to at least a part of the air-side of the first layer (A).

The glazing may be combined with a light source in order to form a lighting unit. When used in a lighting unit, light may be coupled into the glazing from at least one of the edges. Preferably, light is coupled into the glazing such that the light exhibits internal reflection, especially total internal reflection. Light is partially absorbed and re-emitted by the luminous coating. The luminous coating emits the light at arbitrary angles, thus allowing the re-emitted light to exit the glazing. By use of the luminous coating, the light is intentionally scattered so that the re-emitted light does not exhibit total internal reflection.

Unfortunately, light is not only scattered by the luminous coating, but also by impurities on the tin side of material produced in a float glass process. In a float glass process, molten glass material floats on a bed of molten metal, typically tin. The side of the glass material which has faced the bed of molten metal is called tin-side and the opposite side is called air-side. A small quantity of the metal diffuses into the glass material and forms impurities which may scatter light. Tin impurities in float glass may be easily detected by shining short wavelength (for example 254 nm) UV light onto the glass surface. The tin-side fluoresces under UV-light wherein the air-side does not. It has been found that undesired scattering of light in the glazing of the present invention is reduced by applying the luminous coating to the air-side of the first layer (A) which is an optically transparent material being produced in a float glass process. Detailed description of the luminous coating:

The luminous coating preferably comprises at least one inorganic luminescent colorant embedded in a matrix material, wherein the matrix material is a glass.

Additionally, the luminous coating preferably comprises at least one grit. Grit in the meaning of the present application is a scattering body.

The luminous coating may cover the complete surface of the air-side of the first layer (A), i.e. 100% of the area of the first layer (A). However, it is also possible that only a part of the surface of the first layer (A) is covered by the luminous coating. Therefore, for example 0.5 to 50%, preferably 1 to 40 %, more preferably 2 to 30%, most preferably 3 to 25% and even most preferably 4 to 20% of the surface of the first layer (A) are covered by the luminous coating. The luminous coating may be uniformly applied to the first layer (A). Alternatively, the luminous coating may be selectively applied so that certain patterns and/or shapes such as letters or images are formed.

Preferably, the luminous coating has a thickness of from 100 nm to 50 μηη and especially preferably of from 5 μηη to 20 μηη.

Further, the luminous coating may be at least partially embedded in the first layer (A). For example, at least parts of the luminous coating may diffuse into the first layer (A) or the first layer (A) may be softened or partially melted in a heat treatment so that at least parts of the lumi- nous coating may be embedded into the material of the first layer (A).

Matrix material:

Preferably, the glass used as matrix material is free from lead, cadmium and/or lithium.

Such glass materials include, for example, bismuth oxide-based glasses. Suitable glass material my comprise bismuth oxide, silicon oxide and/or tellurium oxide. The proportion of tellurium oxide in the glass is preferably in the range from 0.01 to 10% by weight. The proportion of bismuth oxide in the glass is preferably in the range from 40 to 95% by weight. The proportion of bismuth oxide is more preferably in the range from 50 to 80% by weight and especially in the range from 60 to 75% by weight. The proportion of silicon oxide in the glass is preferably in the range from 0 to 30% by weight, especially in the range from 1 to 4% by weight, based in each case on the mass of the glass. In addition to bismuth oxide, silicon oxide and tellurium oxide, the glass material may additionally comprise boron oxide. The proportion of boron oxide in the glass is preferably in the range from 0.1 to 10% by weight, especially in the range from 0.5 to 8% by weight and in a particularly preferred embodiment in the range from 1 to 4% by weight. In addition to the oxides mentioned, the glass material may comprise zinc oxide and/or aluminum oxide. The proportion of zinc oxide is in the range from 0 to 15% by weight and the proportion of aluminum oxide in the range from 0 to 3% by weight.

Preferred glass materials have a transformation point T _g of less than 500°C. Glass materials having a transformation point in the range of from 470°C to 490°C are especially preferred.

Suitable matrix materials are known in the art. For example, EP 0728710 A1 discloses a lead- free glass composition which is essentially free from L12O, PbO and CdO. The minimum melting temperature of the described glass composition during the 3-minute firing is between 600°C and 630°C.

Luminescent colorant:

The luminous coating comprises at least one inorganic luminescent colorant, whereby luminescent means fluorescent or phosphorescent.

Preferred inorganic luminescent colorants according to the present invention show the following features:

Excitation by light;

High luminescence (i. e. fluorescence or phosphorescence) after excitation; preferred are photoluminescence quantum yields of 50% to 100%, more preferred of 70% to 100%, most preferred of 80% to 100%;

An absorption spectrum in the ultraviolet and visible region of the electromagnetic spectrum, with a maximum absorption at a wavelength of 250 - 800 nm, more preferably 350 - 550 nm, most preferably 400 - 475 nm.

An emission spectrum in the visible region of the electromagnetic spectrum with a maxi- mum emission at a wavelength at 400 - 800 nm, more preferably 410 - 750 nm, most preferably 430 - 630 nm.

Preferred inorganic luminescent colorants are those from the class of the rare earth-doped alu- minates, silicates, nitrides and garnets. Further inorganic luminescent colorants are, for exam- pie, those mentioned in "Luminescence - from Theory to Applications", Cees Ronda [ed.], Wiley-VCH, 2008, Chapter 7, "Luminescent Materials for Phosphor - Converted LEDs", Th. Justel, pages 179-190.

Garnets are compounds of the general formula XsY2[Z0 ₄ ]3 in which Z is a divalent cation such as Ca, Mg, Fe, Mn, Y is a trivalent cation such as Al, Fe, Cr, rare earths, and Z is Si, Al, Fe ³⁺ , Ga ³⁺ . The garnet is preferably yttrium aluminum garnet Y3AI5O12 doped with Ce ³⁺ , Gd ³⁺ , Sm ³⁺ , Eu ²⁺ , Eu ³⁺ , Dy ³⁺ , Tb ³⁺ or mixtures thereof. Suitable nitrides are described, for example, in US 8,274,215. Suitable silicates are described, for example, in US 7,906,041 and US 7,31 1 ,858.

Suitable aluminates are described, for example, in US 7,755,276.

Suitable aluminate phosphors of the formula SrLu2-xAI ₄ 0i2:Ce _x in which x is a value from the range from 0.01 to 0.15 are known from WO2012010244. Luminescent colorants of the composition MLn2QR40i2 where M is at least one of the elements Mg, Ca, Sr or Ba, Ln is at least one of the elements Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; Q is one of the elements Si, Ge, Sn, and Pb, and R, finally, is at least one of the elements B, Al, Ga, In and Tl are known from US 2004/0062699.

Further preferred inorganic luminescent colorants are silicate-based phosphors of a general composition A3Si(0,D) ₅ or A2Si(0,D) ₄ , in which Si is silicon, O is oxygen, A comprises strontium (Sr), barium (Ba), magnesium (Mg) or calcium (Ca) and D comprises chlorine (CI), fluorine (F), nitrogen (N) or sulfur, aluminum-based phosphors, aluminum-silicate-based phosphors, nitride- based phosphors, sulfate phosphors, oxy-nitride phosphors, oxy-sulfate phosphors, garnet materials, iron oxides, titanium dioxide, lead chromate pigments, lead molybdate pigments, nickel titanium pigments or chromium oxide or mixtures thereof.

Suitable inorganic pigments are for example described in US 8,337,029B2 and in EP 2 1 10 237 A1 .

More preferred inorganic luminescent colorants are yttrium aluminum garnets (Y3AI5O12), ceri- um-doped yttrium aluminum garnets (Y3AI5O12 : Ce ³⁺ ), lutetium aluminum garnet (AI5LU3O12), europium doped strontium-barium-nitride-silicate, ASiO : EuF (wherein A is defined above and EuF is doped into ASiO), preferably A is Sr, Ba and C or Ca, BaEuAIO : F (wherein F is doped into BaEuAIO) and MgAIZr : CeF (wherein CeF is doped into MgAIZr). Further, preferred inorganic luminescent colorants include inorganic quantum dots, especially based on CdSe, CdTe, ZnS, InP, PbS, CdS or mixtures thereof.

Inorganic quantum dots are for example described in WO 2013/078252 A1 . Preferred inorganic quantum dots are based on CdSe, CdTe, ZnS, InP, PbS, CdS or mixtures thereof. The quantum dots usually have an average diameter of less than 100 nm, preferably less than 20 nm, more preferably less than 10 nm, for example 2 to 10 nm.

Most preferred inorganic luminescent colorants are cerium-doped yttrium aluminum garnets

Suitable inorganic quantum dots usually have a mean particle size according to DIN

13320:2009-10 of 2 to 30 nm. Suitable inorganic pigments usually have a mean particle size according to DIN 13320 of 0.5 to 50 μηη, preferably 2 to 20 μηη, even more preferably between 5 and 15 μηη.

In the luminous coating the inorganic luminescent colorant is embedded in the glass matrix.

Surprisingly, it has been found that the inorganic luminescent colorant is sufficiently stable in the basic environment of the glass matrix. Further, it has been found that the inorganic luminescent colorant does not decompose when the glass matrix material is formed, by firing a glass frit. Grit (scattering bodies):

Grit in the meaning of the present application is a scattering body.

As at least one grit usually all suitable grit material known in the art can be employed.

Preferably, the grit is selected from particles comprising Ti0 ₂ , Sn0 ₂ , ZnO, AI2O3, Y3AI5O12, Zr02, barium sulfate, lithopone, zinc sulfide, calcium carbonate and mixtures thereof.

The grits are usually colored (for example red, green or blue) pigments or white pigments. Pre- ferably, the grits are white pigments, preferably selected from Ti0 ₂ , ZnO, AI2O3, Y3AI5O12, barium sulfate, lithopone, zinc sulfide, calcium carbonate and mixtures thereof.

Usually, the grit has a mean particle size according to DIN 13320 of 0.01 to 30 μηη, preferably 0.5 to 10 μηη, more preferably 1 to 10 μηη.

In a preferred embodiment, the luminous coating comprises a combination of at least two inorganic luminescent colorants or at least one inorganic luminescent colorant and at least one grit. In a preferred example, cerium-doped yttrium aluminum garnets (Y3AI5O12 : Ce ³⁺ ) serve as inorganic luminescent colorant and are combined with yttrium aluminum garnets (Y3AI5O12), serving as grit.

In a preferred embodiment, the inorganic luminescent colorants are combined with one another such that blue light can be converted to white light with a color temperature of 1500 - 8500 K and good color rendering.

In a preferred embodiment, the inorganic luminescent colorants and/or the grits are combined with one another such that white light (LED light) with a color temperature of 8000 to 15000 K can be converted to white light with a color temperature of 1500 to 7500 K and good color rendering.

In a further preferred embodiment the inorganic luminescent colorants and/or the grits are combined with one another such that blue light (LED light) with usually 440 to 475 nm peak wavelength can be converted to white light, for example by using a yellow converter. In a further preferred embodiment the inorganic luminescent colorants and/or the grits are combined with one another such that red, green and blue light (LED light) can be converted to each color desired.

In a preferred embodiment the glazing comprises a composite structure of laminated layers, the composite structure of laminated layers comprising the first layer (A), a second layer (B), and an interlayer (C), wherein the interlayer (C) is sandwiched between the first layer (A) and the second layer (B) and is arranged parallel to the first layer (A) and the second layer (B), wherein the air-side of the first layer (A), which is at least partially coated with the luminous coating, is laminated to a first side of the interlayer (C).

Such a composite structure of laminated layers may be prepared using lamination processes for producing laminated safety glasses which are known in the art. Especially the interlayer (C) is preferably based on layers usually used in laminated safety glasses. The glazing having a composite structure of laminated layers may be combined with a light source in order to form a lighting unit. Such lighting units may be used in the architectural, e.g. buildings and furniture, or transportation or automotive or aeronautic field. It has been found that undesired scattering of light in the glazing having a composite structure is reduced by applying the luminous coating to the air-side of the first layer (A) which is an optically transparent material being produced in a float glass process and by laminating the coated air-side of the first layer (A) to the interlayer (C). The material of the second layer (B) is preferably optically transparent. Examples for suitable materials of the second layer (B) are transparent polymers and transparent materials obtained in a float glass process.

If the material of the second layer (B) is also an optically transparent layer produced in a float glass process having an air-side and a tin-side, it is preferred to laminate the air side of the second layer (B) to a second side of the interlayer (C).

If the material of the second layer (B) is also an optically transparent layer produced in a float glass process having an air-side and a tin-side and having an additional coating e.g. but not solely sun protecting or low-e or color coating, on the air side, it is preferred to laminate the tin side of the second layer (B) to a second side of the interlayer (C).

If the material of the second layer (B) is based on a transparent polymer, either side of the second layer (B) may be laminated to the second side of the interlayer (C).

Further, the luminous coating may additionally be applied to at least a part of the second layer (B). The luminous coating is preferably applied to the respective side or face of the second layer (B) which faces the interlayer (C) in the composite structure. Thus, in case the second layer (B) is a material produced in a float glass process, the luminous coating is applied to the air-side.

The transparent polymer is preferably selected from the group comprising PVC (polyvinylchlo- ride), PMMA (polymethyl methacrylate), PC (polycarbonate), PS (polystyrene), PPO (polypropylene oxide), PE (polyethylene), LDPE (low density polyethylene), LLDPE (linear low density polyethylene), PEN (polyethylene naphthalate), PP (polypropylene), LDPP (low density polypropylene), PET (polypropylene terephthalate), glycol modified polyethylene terephthalate, PES (polyether sulfones), PI (polyimides) and mixtures thereof.

A suitable PMMA is commercially available under the trade name Plexiglas. The first layer (A) and/or the second layer (B), if the second layer (B) is produced in a float glass process, is preferably selected from the group comprising low-iron glass, glass with an optical transmission >90%, heat strengthened glass and chemically strengthened glass.

Suitable low iron float glass is available under the trade names e.g. Pilkington Optiwhite, Guardian UltraClear Float Glass, SGG Planiclear, SGG Diamont.

Low-iron glass or "white glass" is a type of high-clarity glass that is made from silica with very low amounts of iron. This low level of iron removes the greenish-blue tint that can be seen especially on larger and thicker sizes of normal glass. Low-iron glass has a low iron content of less than 500 ppm (0.05%), preferably less than 200 ppm (0.02%) and especially preferred less than 100 ppm (0.01 %). Optionally, the first layer (A) and/or the second layer (B) is coated with at least one functional layer. The functional layer is preferably a color effect coating, low-emissivity (low-e) coating, sun-protection coating, metal coating, metal oxide coating or any other coating. In case of the first layer (A), the functional layer is applied to the tin-side. Thus, in a composite structure, the functional layer is facing away from the interlayer (C). In case of the second layer (B) in a com- posite structure, the functional layer is located on the surface facing away from the interlayer

(C) .

The layer thickness of the first layer (A) is preferably 0.1 to 50 mm, more preferably 0.5 to 30 mm, most preferably 1 .5 to 12 mm.

The layer thickness of the second layer (B) is preferably 0.1 to 50 mm, more preferably 0.5 to 30 mm, most preferably 1 .5 to 12 mm.

The area of the first layer (A) and second layer (B) may be the same or different and is preferably the same. The area is usually 0.05 to 25 m ² , preferably 0.08 to 15 m ² , more preferably 0.09 to 10 m ² . At least one dimension of first layer (A) and second layer (B) is usually 0.1 to 10 m, preferably 0.25 to 5 m, more preferably 0.3 to 3 m.

The first layer (A) and/or second layer (B) might have an additional imprint.

An additional film might be located on the optically transparent layer (A) and/or (B). The film might be imprinted, having a certain optical transparency e.g. but not limited to for advertisements using the invention as backlight. The light transmission of the first layer (A) and/or the second layer (B) is preferably at least 30%, preferably 30% to 100%, more preferably at least 50%, even more preferably 50% to 100%, most preferably at least 80%, even more most preferably 90% to 100%. The light transmission is preferably determined as light transmission TL for visible light based on EN

410:201 1 . The wavelength of visible light is from 380 nm to 780 nm.

It is possible that not the complete first layer (A) and/or second layer (B) is optically transparent, but only a part of layer (A) and/or (B). Further, it is possible that only the first layer (A) is optically transparent and the second layer (B) is opaque. Suitable examples for an opaque second layer (B) include polished glass (metal coated glass), a metal foil, a metal sheet or frosted glass, respectively partially frosted glass. Further, non- transparent polymer layers may be used.

However, preferably both first layer (A) and second layer (B) are optically transparent and se- lected from an optically transparent material.

It is also possible that the transparency is wavelength sensitive, i.e. optically transparent also means that the light transmission mentioned before is only for yellow light or only for green light or only for red light or only for blue light, but the light transmission is lower for light of other wavelengths. This is for example the case when first layer (A) and/or second layer (B) is a wavelength sensitive glass, for example a toned glass layer. It is also possible to use wavelength sensitive polymer layers, for example toned polymer layers.

At least one of the first layer (A) or second layer (B) may comprise one or more functional fea- tures like a coating or printing for decorative or informative purposes, a sensor element for pressure (touch panel), heat, light, humidity, pH-value -for example to switch the light source-, or an integrated solar cell or a solar cell foil, for example for power supply of the light source. The first layer (A) and the second layer (B) usually have independently of each other a thickness of 0.1 to 50 mm, preferably 0.5 to 30 mm, more preferably 1 .5 to 12 mm.

Interlayer (C) In embodiments of the glazing comprising a composite structure of laminated layers, the interlayer (C) is arranged between the first layer (A) and the second layer (B) and is arranged parallel to the first layer (A) and second layer (B). The air-side of the first layer (A), which is at least partially coated with a luminous coating, faces the interlayer (C).

The interlayer (C) may be of any material which is useful in laminated glass. Therefore, suitable materials for the interlayer (C) are known by a person skilled in the art. The advantage of the present invention is that material for the first layer (A), second layer (B), and interlayer (C) may be used which are usually employed in laminated glass.

Preferably, the interlayer (C) is based on an ionomer (ionoplast), polymethlymethacrylate (PMMA), acid copolymers of a-olefins and α,β-ethylenically unsaturated carboxylic acids, ethylene vinyl acetate (EVA), polyvinyl acetal (for example poly(vinylbutyral)) (PVB), including acoustic grades of polyvinyl acetal), thermoplastic polyurethane (TPU), polyethylenes (for example metallocene-catalyzed linear low density polyethylenes), polyolefin block elastomers, ethylene acrylate ester copolymers (for example poly(ethylene-co-methyl-acrylate) and poly(ethylene-co-butyl acrylate)), silicone elastomers, epoxy resins and mixtures thereof.

Suitable ionomers are derived from acid copolymers. Suitable acid copolymers are copolymers of α-olefins and α,β-ethylenically unsaturated carboxylic acids having 3 to 8 carbon atoms. The acid copolymers usually contain at least 1 % by weight of α,β-ethylenically unsaturated carboxylic acids based on the total weight of the copolymers. Preferably, the acid copolymers contain at least 10% by weight, more preferably 15% to 25% by weight and most preferably 18% to 23% by weight of α,β-ethylenically unsaturated carboxylic acids based on the total weight of the copolymers.

The α-olefins mentioned before usually comprise 2 to 10 carbon atoms. Preferably, the a-olefins are selected from the group consisting of ethylene, propylene, 1 -butene, 1 -pentene, 1 -heptene, 1 -hexene, 3-methyl 1 -butene, 4-methyl-1 -pentene and mixtures thereof. More preferably, the a-olefin is ethylene. The α,β-ethylenically unsaturated carboxylic acids are preferably selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, monomethyl maleic acid and mixtures thereof, preferably acrylic acid, methacrylic acid and mixtures thereof. The acid copolymers may further contain other unsaturated copolymers like methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, octyl acrylate, octyl methacrylate, undecyl acrylate, undecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, dodecyl acrylate, dodecyl methacrylate, 2-ethyl hexyl acrylate, 2-ethyl hexyl methacrylate, iso- bornyl acrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, 2-hydroxy ethyl acrylate, 2-hydroxy ethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, poly(ethylene glycol) acrylate, polyethylene glycol (meth)acrylate, poly(ethylene glycol) methylether acrylate, poly(ethylene glycol) methylether methacrylate, poly(ethylene glycol) ether methacrylate, poly(ethylene glycol)behenyl ether acrylate, poly(ethylene glycol)behenyl ether methacrylate, poly(ethylene glycol)4-nonylphenylether acrylate, poly(ethylene glycol)4-nonylphenylether methacrylate, poly(ethylene glycol)phenyl ether acrylate, poly(ethylene glycol)phenyl ether methacrylate, dimethyl maleate, diethyl maleate, dibutyl maleate, dimethyl fumarate, diethyl fumarate, dibutyl fumarate, dimenthyl fumarate, vinyl acetate, vinyl propionate, and mixtures thereof. Preferably, the other unsaturated comonomers are selected from the group consisting of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl methacrylate, vinyl acetate and mixtures thereof. The acid copolymers may comprise up to 50% by weight, preferably up to 30% by weight, more preferably up to 20% by weight of other unsaturated copolymers, based on the total weight of the copolymer.

The preparation of the acid copolymers mentioned before is known in the art and described for example in US 3,404,134, US 5,028,674, US 6,500,888, and US 6,518,635.

To obtain the ionomers, the acid copolymers are partially or fully neutralized with metallic ions. Preferably, the acid copolymers are 10% to 100%, more preferably 10% to 50%, most preferably 20% to 40% neutralized with metallic ions, based on the total number of moles of carboxy- late groups in the ionomeric copolymer. The metallic ions may be monovalent, divalent, trivalent or multivalent or mixtures of said metallic ions. Preferable monovalent metallic ions are sodium, potassium, lithium, silver, mercury, copper and mixtures thereof. Preferred divalent metallic ions are beryllium, magnesium, calcium, strontium, barium, copper, cadmium, mercury, tin, lead, iron, cobalt, nickel, zinc, and mixtures thereof. Preferred trivalent metallic ions are aluminum, scandium, iron, yttrium and mixtures thereof. Preferred multivalent metallic ions are titanium, zirconium, hafnium, vanadium, tantalum, tungsten, chromium, cerium, iron and mixtures thereof. It is preferred that when the metallic ion is multivalent, complexing agents, such as stearate, oleate, salicylate and phenylate radicals are included (see US 3,404,134). More preferred metallic ions are selected from the group consisting of sodium, lithium, magnesium, zinc, aluminum and mixtures thereof. Furthermore preferred metallic ions are selected from the group consist- ing of sodium, zinc and mixtures thereof. Most preferred is zinc as a metallic ion. The acid copolymers may be neutralized as disclosed for example in US 3,404,134.

The ionomers usually have a melt index (Ml) of, less than 10 g/10 min, preferably less than 5 g/10 min, more preferably less than 3 g/10 min as measured at 190°C by ASTM method D1238. Further, the ionomers usually have a flexural modulus, greater than 40000 psi, preferably greater than 50000 psi, more preferably greater than 60000 psi, as measured by ASTM method D638.

The ionomer resins are typically prepared from acid copolymers having a Ml of less than 60 g/10 min, preferably less than 55 g/10 min, more preferably less than 50 g/10 min, most preferably less than 35 g/10 min, as determined at 190°C by ASTM method D1238.

Suitable ionomers are mentioned in US 8,080,726 B2. Preferably, the interlayer (C) is based on an ionomer, whereby preferred ionomers are mentioned before, polyvinylbutyral (PVB), polyvinylacetal, ethylene-vinylacetate (EVA), ethylene/- vinylalcohol/vinylacetal copolymer and epoxy pouring resins. Commercial materials for the inter- layer (C) are Trosifol ^® , Butacite ^® , Saflex ^® , S-Lec ^® , Everlam ^® and SentryGlas ^® .

The thickness of the interlayer (C) is usually from 0.05 mm to 10 mm, more preferably from 0.2 mm to 6 mm, most preferably from 0.3 mm to 3 mm. Preferably, the interlayer (C) is a laminate comprising at least two layers. The material of each of the layers of the laminate may be selected independently from materials suitable in laminated glass. In particular, the materials disclosed for the interlayer (C) are suitable. The material of the at least two layers may be chosen such that each layer is made from a different material. Alternatively, two or more layers of the same material may be used.

The area of the interlayer (C) may be identical with or different from the area of the first layer (A) and/or second layer (B). Preferably, the area of layers (A), (B) and interlayer (C) are identical. Suitable areas for the interlayer (C) are the same as mentioned for layers (A) and (B). The interlayer (C) may be comprised by several pieces of interlayer of smaller area, tiled side-by-side to be combined to become one larger interlayer.

Adhesion promoter

In embodiments comprising a composite structure of laminated layers, the air side of the first layer (A), which is at least partially coated with the luminous coating, and/or the side of the second layer (B) which is in contact with the interlayer (C) is preferably treated with an adhesion promoter. Especially when the interlayer (C) is based on an ionomer (ionoplast) it is preferred to apply an adhesion promoter to the air-side of the first layer (A). Further, it is preferred to apply the adhesion promoter to the side of the second layer (B) which is in contact with the interlayer (C). Applying the adhesion promoter to the second layer (B) is especially preferred if the second layer has been obtained in a float-glass process and the air-side of the second layer (B) is in contact with the interlayer (C) or if the second layer (B) is a glass not obtained by means of a float glass process. The use of an adhesion promoter for lamination of an interlayer based on an ionomer is usually not required if a float glass is used and the interlayer is laminated to the tin-sides of the glass layers. In laminated safety glass known in the art the used float glass sheets are thus arranged such that the tin-sides face the interlayer in order to avoid the use of an adhesion promoter. A suitable adhesion promoter for lamination of an interlayer (C) based on an ionomer such as SentryGlas ^® is based on gamma-aminopropyltriethoxysilane as active ingredient. For application of the adhesion promoter to a float glass layer, the active ingredient is preferably used in a solution comprising as further components 2-propanol, water and acetic acid. The adhesion promoter solution may for example be applied by spraying the solution onto the surface and subsequently drying the surface.

Preferably, the composite structure of laminated layers consists of in this order a first layer (A), an interlayer (C) and a second layer (B), wherein the air-side of the first layer (A) is at least partially coated with a luminous coating.

Alternatively, the composite structure of laminated layers comprises in this order a first layer (A) an interlayer (C) and a second layer (B), wherein the air-side of the first layer (A) is at least par- tially coated with a luminous coating, and further comprises at least one support layer which is laminated to the first layer (A) or the second layer (B) by means of an additional interlayer. A composite structure consisting of in this order a first layer (A) an interlayer (C) and a second layer (B) may be used as an intermediate product wherein the at least one support layer is laminated to either the first layer (A) or the second layer (B) by means of the additional interlayer. In a preferred embodiment, two support layers are used wherein a first support layer is laminated to the tin-side of the first layer (A) using a first additional interlayer und a second support layer is laminated to the second layer (B) using a second additional interlayer.

The at least one support layer is preferably selected from a transparent polymer, a glass, espe- cially glass produced in a float glass process, metals, or a combination of at least two of these materials. The materials described with respect to the first layer (A) and the second layer (B) are suitable materials for the at least one support layer. In case of the second support layer, the material may also be selected from an opaque material such as, for example polished glass (metal coated glass), a metal foil, a metal sheet or frosted glass, respectively partially frosted glass. Further, non-transparent polymer layers may be used.

The materials described with respect to the interlayer (C) are also suitable for use with the at least one additional interlayer. Preferably, the at least one support layer has a color effect coating, low-emissivity (low-e) coating, sun-protection coating, metal coating, metal oxide coating or any other coating. If the material of the support layer is a material produced in a float glass process it is preferred to apply the coating to the air-side of the support layer. Lighting unit

A further aspect of the invention is providing a lighting unit comprising one of the described glazings and at least one light source arranged at an edge of the glazing. The at least one light source is arranged at the edge of the glazing such that light emitted by the at least one light source is coupled into the laminated glazing. This means that the at least one light source is preferably arranged in a way that the radiation is irradiated parallel to the first layer (A). Preferably, the at least one light source is arranged in the middle of the height of the first layer (A).

If the laminated glazing is of a rectangular shape, the at least one light source may be arranged at one of the four edges of the glazing. Preferably, the lighting unit comprises at least two light sources which are preferably arranged at opposing edges of the glazing.

In the case that more than one light source is employed and more than one light source is arranged on the same edge of the glazing, the light sources are preferably arranged in a line preferably with identical distance to the layers of the glazing.

The number of light sources usually depends on the desired luminous intensity and the efficiency of the light source and the area of the glazing. In the case that the light sources are arranged at two edges of the laminated glazing opposite to each other, it is possible to reduce inhomogeneities for example because of light absorption in the glazing.

The at least one light source may be any light source known by a person skilled in the art as useful for lighting units.

Preferably, the light source is selected from the group consisting of LEDs (light emitting diode), OLEDs (organic light emitting diode), laser and gas-discharge lamps. Preferably, the light source is selected from the group consisting of LEDs and OLEDs, more preferred are LEDs.

Preferred light sources show low power consumption, a low mounting depth and very flexible wavelength ranges, which can be chosen depending on the necessity (a small wavelength range or a broad wavelength range). Suitable wavelength ranges for the light source are for example 430 to 470 nm (blue), 515 to 535 nm (green) and 610 to 630 nm (red). Depending on the desired color of light, for example in the case of white light, light sources with different wavelengths may be combined or light sources having the desired color of light (for example white light) can be employed. The emission spectrum of an OLED may for example selectively adjusted by the device structure of the OLED.

Therefore, the at least one light source preferably emits light in a wavelength range of 250 to 1000 nm, preferably of 360 to 800 nm. More preferably, the light source emits light with a wavelength (peak wavelength) of 360 to 475 nm.

The half width of the emission spectrum of the light source is for example less than 35 nm. In the lighting unit according to the present invention one or more light sources can be used. Preferably, 1 to 200 light sources, more preferably 1 to 100 light sources, most preferably 1 to 50 light sources are used in the lighting unit according to the present application. Said light sources emit in an identical wavelength range or in different wavelength ranges, i.e. said light sources emit with the same color of light or with different colors of light. Preferably, the light sources employed in the lighting unit according to the present application emit in the same color of light or in three different colors of light, i.e. usually red, green and blue. By combination of the emission of red, green and blue emitting light sources desired different light colors can be adjusted.

The at least one light source preferably shows a directional light radiation. The angle of radiation (half value angle) is preferably less than 120° more preferably less than 90°, most preferably less than 45°.

The lighting unit according to the present application comprises in a preferred embodiment at least one optical element which is arranged between the at least one light source and the glazing, at the edge of said glazing. In the case that more than one light source is employed, it is possible to employ also more than one optical element, i.e. preferably as many optical elements as light sources are present.

Suitable optical elements are known by a person skilled in the art. Examples for suitable optical elements are lenses or cylindric lenses. The optical element(s) is (are) placed in the path of light emitted from the light source(s) into the edge of the laminated glazing. The optical element(s) can be attached (e.g. glued) directly to the light source(s), or can be attached (e.g. glued) to one edge of the layer(s) of the glazing, or can be attached to a profile, which fixes the position of light source(s), to the position optical element(s) and of the glazing to each other. In a further preferred embodiment, which may be combined with the preferred embodiment (the presence of at least one optical element) mentioned before, the lighting unit comprises at least one light source at each edge of two edges of the laminated layers, especially at two edges which are opposite to each other. Preparation of the Lighting Unit

The preparation of the lighting unit according to the present application is usually carried out as known in the art. Preferably, the process of preparing the lighting unit according to the present invention comprises the steps of: i) providing a glazing comprising a first layer (A) which is an optically transparent layer produced in a float glass process having an air-side and a tin-side, wherein a luminous coating is applied to at least a part of the air-side;

ii) providing at least one light source;

iii) mounting the at least one light source at an edge of the glazing.

In one embodiment of the present application, the light sources, as well as optional optical elements are fixed to the glazing by a profile, for example by an LED-profile. The lighting unit according to the present application may be used in any useful application for lighting units. Examples for useful applications are the use of a lighting unit according to the present invention in buildings, furniture, cars, trains, planes and ships. In specific, present invention is useful in all applications, in which illuminated glass is of benefit. The lighting units according to the present application are for example used in facades, skylights, glass roofs, stair treads, glass bridges, canopies, railings, car windows and train windows.

The present invention therefore further relates to the use of the inventive lighting unit in build- ings, furniture, cars, trains, planes and ships as well as to the use of the inventive lighting unit in facades, skylights, glass roofs, stair treads, glass bridges, canopies, railings, car glazing, train glazing.

The present invention further relates to the use of the inventive lighting unit for control of radia- tion, especially UV radiation (100-400 nm), visible radiation (400 nm to 700 nm) and infrared radiation (700 nm to 1 mm), i.e. near infrared (700 nm to 1400 nm), short wave length infrared (1 .4 μηη to 3 μηη), mid length infrared (3 μηη to 8 μηη), long wave length infrared (8 μηη to 15 μηη) and far infrared (15 μηη to 1000 μηη), for optical control and/or for acoustical control. The present invention further relates to the use of the inventive lighting unit in insulating glass units, windows, rotating windows, turn windows, tilt windows, top-hung windows, swinging windows, box windows, horizontal sliding windows, vertical sliding windows, quarterlights, store windows, skylights, light domes, doors, horizontal sliding doors in double-skin facades, closed cavity facades, all-glass constructions, D3-facades (Dual, Dynamic Durable Facade), facade glass construction elements (e.g. but not limited to fins, louvres), interactive facades (facades reacting on an external impulse e.g. but not limited to a motion control, a radio sensor, other sensors) curved glazing, formed glazing, 3D three-dimensional glazing, wood-glass combinations, over head glazing, roof glazing, bus stops, shower wall, indoor walls, indoor separating elements in open space offices and rooms, outdoor walls, stair treads, glass bridges, canopies, railings, aquaria, balconies, privacy glass and figured glass.

The present invention further relates to the use of the inventive lighting unit for thermal insulation, i.e. insulation against heat, insulation against cold, sound insulation, shading and/or sight protection. The present invention is preferably useful when combined with further glass layers to an insulation glass unit (IGU), which can be used for building facades. The IGU might have a double (Pane 1 + Pane 2), or triple glazing (Pane 1 + Pane 2 + Pane 3), or more panes. The panes might have different thicknesses and different sizes. The panes might be of tempered glass, tempered safety glass, laminated glass, laminated tempered glass, safety glass. The lighting unit according to the present application may be used in any of the Panes 1 , 2, 3. Materials can be put into the space between the panes. For example, but not limited such materials might be wooden objects, metal objects, expanded metal, prismatic objects, blinds, louvres, light guiding objects, light guiding films, light guiding blinds, 3-D light guiding objects, sun pro- tecting blinds, movable blinds, roller blinds, roller blinds from films, translucent materials, capillary objects, honey comb objects, micro blinds, micro lamella, micro shade, micro mirrors insulation materials, aerogel, integrated vacuum insulation panels, holographic elements, integrated photovoltaics or combinations thereof. The present invention further relates to the use of the inventive lighting unit in advertising panels, showcases, display facades, interactive facades, interactive bus stops, interactive train stations, interactive meeting points, interactive surfaces, motion sensors, light surfaces and background lighting, signage, pass protection. Optionally, a film and/or an imprinted film might be put on one or more surfaces.

The present invention further relates to the use of the inventive lighting unit in heat-mirror glazing, vacuum glazing, multiple glazing and laminated safety glass.

The present invention further relates to the use of the inventive lighting unit in transportation units, preferably in boats, in vessels, in spacecrafts, in aircrafts, in trains, in automotive, in trucks, in cars e.g. but not limited to windows, separating walls, light surfaces and background lighting, signage, pass protection, as sunroof, in the trunk lid, in the tailgate, for brake lights, for blinker, for position lights in said transportation units. Optional a film and/or an imprinted film might be put on one or more surfaces.

The present invention is preferentially useful when combined with further glass layers to an insulation glass unit (IGU), which can be used for building facades.

Preparation of the glazing

A further aspect of the invention is providing a method for producing a glazing having at least a first layer (A), which is an optically transparent layer produced in a float glass process having a tin-side and an air-side and wherein a luminous coating is applied to the air-side of the first layer (A).

The method for producing a glazing comprises the steps of: a. providing a first layer (A), wherein the first layer (A) is an optically transparent layer produced in a float glass process having an air-side and a tin-side,

b. applying a luminous paint to at least a part of the air-side of the first layer (A),

c. heat treating the first layer (A), and

d. cooling of the first layer (A).

The first layer (A) is a material obtained in a float glass process as described in conjunction with the glazing. Luminous paint

The luminous paint preferably comprises a glass frit and at least one inorganic luminescent colorant. The luminous paint preferably additionally comprises at least one grit. The grit is a scattering body as described with respect to the glazing.

Usually, the glass frit, the at least one inorganic luminescent colorant and, if present, the at least one grit, are suspended in a continuous phase. The continuous phase is used to suspend the solid glass frit and the solid inorganic luminescent colorant in a fluid medium in an amount effective to achieve a consistency suitable for applying the luminous paint to the air-side of the first layer (A).

Glass frit

Glass frits are known in the art for the decoration of glass articles, particularly glass plates. The glass frit and at least one inorganic colorant are coated to a glass plate and are then baked, whereby a glass-enamel is formed.

Preferably, the amount of glass frit in the luminous paint is from 0.1 % by weight to 90% by weight. Especially preferred 10% by weight to 80% by weight and most preferred 30% by weight to 60% by weight.

Preferably, the glass used as matrix material is free from lead, cadmium and/or lithium. Essentially free in the context of the present invention means that no lead, cadmium and/or lithium is added to the glass frit and the proportion of lead, cadmium and/or lithium, respectively, in the glass frit is less than 1000 ppm.

Such glass frits are, for example, bismuth oxide-based glasses. Suitable glass frits my comprise bismuth oxide, silicon oxide and/or tellurium oxide. The proportion of tellurium oxide in the glass frit is preferably in the range from 0.01 to 10% by weight. The proportion of bismuth oxide in the glass frit is preferably in the range from 40 to 95% by weight. The proportion of bismuth oxide is more preferably in the range from 50 to 80% by weight and especially in the range from 60 to 75% by weight. The proportion of silicon oxide in the glass frit is preferably in the range from 0 to 30% by weight, especially in the range from 1 to 4% by weight, based in each case on the mass of the glass frit.

In addition to bismuth oxide, silicon oxide and tellurium oxide, the glass frit may additionally comprise boron oxide. The proportion of boron oxide in the glass frit is preferably in the range from 0.1 to 10% by weight, especially in the range from 0.5 to 8% by weight and in a particularly preferred embodiment in the range from 1 to 4% by weight.

In addition to the oxides mentioned, the glass frit may comprise zinc oxide and/or aluminum oxide. The proportion of zinc oxide is in the range from 0 to 15% by weight and the proportion of aluminum oxide in the range from 0 to 3% by weight.

Preferred glass materials have a transformation point T _g of less than 500°C. Glass materials having a transformation point in the range of from 470°C to 490°C are especially preferred.

Preferred glass frits are glass frits having a minimum melting temperature Ts, which is determined in a 3 minute bake on glass, of less than 700°C. Especially preferred glass frits have a minimum melting temperature Ts in the range of from 600°C to 630°C. The minimum melting temperature Ts may be determined in a 3 minute bake on glass as the substrate, wherein the pore freedom of the molten glass frit baked with the glass is referred to as the judgement criterion.

Suitable glass frits are known in the art. For example, EP 0728710 A1 discloses a lead-free glass frit which is essentially free from U2O, PbO and CdO.

Preferably, the glass frit is provided in form of a powder, in form of glass spheres or in form of hollow glass spheres. The glass frit and the pigments generally have the form of powder before they are dissolved in a medium. The grain size distribution of the total of frit (s) / pigment (s) in powder form is generally selected such that at least 90% by weight of the particles containing the powder have a diameter of less than 20 μηη, in particular less than 10 μηη. Preferably, the glass frit and the pigment(s) of particles having a grain size which ranges from 0.001 to 200 μηη, especially preferred 0.01 to 70 μηη, most preferred 0.1 to 10 μηη.

Grit

The grit is a scattering body as described with respect to the glazing.

Preferably, the amount of grit in the luminous paint is from 0% by weight to 60% by weight. Especially preferred 1 % by weight to 55% by weight, most preferred 2% by weight to 50% by weight. Preferably, the at least one grit is selected from particles comprising ΤΊ02, Sn02, ZnO, AI203, Y3AI5012, barium sulfate, lithopone, zinc sulfide, calcium carbonate, Zr02 and mixtures thereof.

Luminescent colorant

The luminescent colorant is preferably an inorganic luminescent colorant as described with respect to the glazing.

Preferably, the amount of luminescent colorant in the luminous paint is from 10 % by weight to 80% by weight. Especially preferred, the amount of luminescent colorant in the luminous paint is from 30 % by weight to 70 % by weight and most preferred from 40% by weight to 65 % by weight.

Preferred inorganic luminescent colorants are yttrium aluminum garnets (Y3AI5O12), cerium- doped yttrium aluminum garnets (Y3AI5O12 : Ce ³⁺ ), lutetium aluminum garnet (AI5LU3O12), europium doped strontium-barium-nitride-silicate, ASiO : EuF (wherein A is defined above and EuF is doped into ASiO), preferably A is Sr, Ba and C or Ca, BaEuAIO : F (wherein F is doped into BaEuAIO) and MgAIZr : CeF (wherein CeF is doped into MgAIZr).

Continuous phase

The continuous phase is used to suspend the solid glass frit and the solid inorganic luminescent colorant in a fluid medium in an amount effective to achieve a consistency suitable for applying the luminous paint to the air-side of the first layer (A).

Preferably, the continuous phase is selected such that it may be evaporated after the luminous paint has been applied. Additionally or alternatively, the continuous phase is selected such that it may be burned without residue.

Preferably, the continuous phase is selected from the group comprising water, organic solvents, inorganic solvents, polymers, wax, oils and mixtures thereof. Suitable organic solvents are for example alkanols, like n- and i-alkanols, for example ethanol, iso-propanol, n-propanol, n-butanal; texanol; butylcarbitol; etherol or alcohol based acetates like butylcarbitol acetate, methoxypropyl acetate, propylene glycol methylether acetate, propylene glycol diacetate; dipropylene glycol dimethyl ether; glyme, diglyme; or linear or branched alkyl acetates with 3 to 22 carbon atoms.

Preferred examples of suitable continuous phases include mixtures of water and water-soluble or water-dispersible polymers or polymer mixtures. Suitable polymers which can be used in the continuous phase include, for example, acrylate dispersions and acrylate copolymers, for example styrene acrylates, alkali-soluble acrylate resins and copolymers thereof, maleic anhydride copolymers, for example styrene-maleic acid dispersions, alkyd resin dispersions, styrene- butadiene dispersions, cellulose derivatives, especially hydroxyalkylcelluloses, carboxyalkyl- celluloses, polyester dispersions, polyvinyl alcohols, especially partly or fully hydrolyzed poly- vinyl alcohols, hydrolyzed vinyl acetate copolymers, for example grafted polyethylene glycol- vinyl acetate copolymers, polyvinylpyrrolidone and vinylpyrrolidone copolymers, polyethylene- imines, polyvinylamine, polyvinylformamide, hyperbranched polycarbonates, polyglycols, poly- urethane dispersions, proteins, for example casein. It is also possible for mixtures of two or more polymers to form the continuous phase.

Other examples of suitable continuous phases include monomers, oligomers, polymers and combinations thereof which may be cured by means of UV light. A luminous paint including such a polymer as continuous phase may be cured and thus immobilized before subsequent handling such as heating the first layer (A) is performed. The curable continuous phase may additionally comprise at least one photoinitiator.

A further example of a suitable continuous phase is screen printing oil which is known in the art. For example, a screen printing oil comprising 1 1 parts by weight of ethyl cellulose, 86.5 parts by weight of butyl lactate and 2.5 parts by weight of polyethylene glycol (M - 100 000, particle size 0.3-1 .5 microns) is known from EP 0099471 B1 .

In addition, the luminous paint may also comprise further additives. Additives which may be present in the luminous paint are, for example, dispersants, thixotropic agents, plasticizers, wetting agents, defoamers, desiccants, crosslinkers and/or complexing agents. The additives may each be used individually or as a mixture of two or more of the additives.

The proportion of the additives in the composition is generally in the range from 0 to 5% by weight, preferably in the range from 0.1 to 3% by weight and especially in the range from 0.1 to 2% by weight.

When a dispersant is used as an additive, it is possible to use only one dispersant or more than one dispersant.

In principle, all dispersants which are known to the person skilled in the art for use in disper- sions and are described in the prior art are suitable. Preferred dispersants are surfactants or surfactant mixtures, for example anionic, cationic, amphoteric or nonionic surfactants. Suitable cationic and anionic surfactants are described, for example, in "Encyclopedia of Polymer Science and Technology", J. Wiley & Sons (1966), Volume 5, pages 816 to 818 and in "Emulsion Polymerisation and Emulsion Polymers", editors: P. Lovell and M. El-Asser, publisher: Wiley & Sons (1997), pages 224 to 226. However, it is also possible to use polymers with pigment- affinitive anchor groups, which are known to the person skilled in the art, as dispersants. When thixotropic agents are added as an additive, it is possible, for example, to use organic thixotropic agents. Thickeners which can be used are, for example, polyacrylic acid, poly- urethanes or hydrogenated castor oil. Plasticizers, wetting agents, defoamers, desiccants, crosslinkers, complexing agents and conductive polymer particles which can be used are those as are typically used in dispersions and are known to the person skilled in the art.

Examples of suitable continuous phases include:

(i)

a-Terpineol (70 to 90 % by weight, based on the total amount of the continuous phase), EFKA PX 4330 (70%) (0.1 to 5 % by weight, based on the total amount of the continuous phase),

ETHOCEL Std 4 Industrial (0.5 to 10 % by weight, based on the total amount of the continuous phase) and

DISPARLON 6700 (0.5 to 10 % by weight, based on the total amount of the continuous phase), (ii)

Diacetin (70 to 90% by weight),

EFKA PX 4330 (70%) (0.1 to 5 % by weight, based on the total amount of the continuous phase),

ETHOCEL Std 4 Industrial (0.5 to 10% by weight, based on the total amount of the continuous phase), and

DISPARLON 6700 (0.5 to 10% by weight, based on the total amount of the continuous phase).

(iii)

a-Terpineol (70 to 90% by weight, based on the total amount of the continuous phase), Solsperse 36000 (0.1 to 5% by weight, based on the total amount of the continuous phase), ETHOCEL Std 4 Industrial (0.5 to 10% by weight, based on the total amount of the continuous phase), and

DISPARLON 6700 (0.5 to 10% by weight, based on the total amount of the continuous phase), (iv)

a-Terpineol (70 to 90% by weight, based on the total amount of the continuous phase), Disperbyk 180 (0.1 to 5% by weight, based on the total amount of the continuous phase),

ETHOCEL Std 4 Industrial (0.5 to 10% by weight, based on the total amount of the continuous phase), and

DISPARLON 6700 (0.5 to 10% by weight, based on the total amount of the continuous phase). (v)

a-Terpineol (70 to 90% by weight, based on the total amount of the continuous phase), Disperbyk 2022 (0.1 to 5% by weight, based on the total amount of the continuous phase), ETHOCEL Std 4 Industrial (0.5 to 10% by weight, based on the total amount of the continuous phase), and

DISPARLON 6700 (0.5 to 10% by weight, based on the total amount of the continuous phase). (vi)

Butylcarbitol (90 parts by weight),

Ethylcellulose (10 parts by weight).

(νϋ)

Dipropylene glycol dimethyl ether (90 parts by weight),

Ethylcellulose (10 parts by weight),

Solsperse 36000 = polyamine dispersant

Ethocel = ethyl cellulose

Disparlon 6700 = fatty acid diamide of ethylene diamine

Disperbyk 180 = oligomeric MPEG-phosphate dispersant

wherein a is 0 or an integer from 1 to 5, and b and c are independent of each other integers from 1 to 14, and n is 1 to 5.

Disperbyk 2022 = acrylate copolymer dispersant

Amine value: 61 mg KOH/g

MW = 9000 g/mol, PDI = 1.6

Composition: by ¹ H-NMR

Preferably, the luminous paint is applied in step b) by means of screen printing, digital printing, inkjet printing, slot-die coating, slit coating, spin coating, gravure printing, flexo print, roller coating, curtain coating or spraying. The luminous paint is preferably homogeneously distributed. It is also possible to apply the luminous paint only to a part of the first layer (A) or in form of pattern as mentioned above.

After application of the luminous paint according to step b) a heating step c) is performed in which the continuous phase of the luminous paint is evaporated and/or burned without residues. Further, the glass frit is heated to a temperature above the minimum melting temperature Ts of the glass frit such that the resulting coating is free of pores after the temperature bake.

The heating step may be performed by a process known in the art, e.g. by heating under ambi- ent or by heating under laminar gas flow, or by heating under controlled atmosphere e.g. under a vacuum.

If a furnace is used to perform the heating step, the glass is usually placed onto a roller table, taking it through the furnace.

In the cooling step d) the cooling of the first-layer may be performed by radiative cooling. The cooling may be accelerated by additionally allowing convection cooling. Further, forced convection are a cooling medium may be used to further accelerate the cooling process. An example for a suitable cooling medium is air. High pressure air may be directed onto the first-layer by a plurality of nozzles.

Preferably, the first layer (A) is heated to a temperature above the transformation point T _g of the first layer (A) in step c) and is subsequently air-quenched in step d). Depending on the cooling rate, the first layer (A) may be formed into heat-strengthened glass or into tempered glass. Pre- ferably, the temperature for the heating step is in the range of from 600°C to 650°C. Typically, a temperature of about 630°C is used.

For tempered glass, the cooling process is accelerated when compared to the formation of heat strengthened glass. In both cases a high surface compression is created in the glass, wherein the rapid cooling of the production of tempered glass creates a higher surface compression in the glass. Tempered glass is used as safety glazing. When broken, safety glazing fractures into relatively small pieces, thereby greatly reducing the likelihood of serious cutting or piercing injuries in comparison to ordinary glass. Heat strengthened glass has an improved strength when compared to ordinary glass, but exhibits a similar breakage pattern than ordinary glass.

Preferred embodiments of the glazing comprise a composite structure of laminated layers. For producing such a composite structure, the method for producing a glazing comprises the additional steps of: e) providing an interlayer (C) and a second layer (B),

f) laminating the air side of the first layer (A) to the interlayer (C) and laminating the second layer (B) to the interlayer (C) so that the interlayer (C) is sandwiched between the first layer (A) and the second layer (B) and is arranged parallel to the first layer (A) and the second layer (B).

Suitable interlayers (C) and second layers (B) have already been described with respect to the glazing.

The layers of the composite structure are laminated by any process known in the art, for example by stacking of the layers of the laminated glazing and laminating by for example placing it under vacuum in a vacuum bag and backing it in an autoclave, for example at 100 to 180°C and for example at a pressure of from 2 to 20 bar and/or for example for 0.5 to 10 hours.

Brief description of the drawings

Figure 1 shows a first embodiment of the glazing,

Figure 2 shows a second embodiment of the glazing,

Figure 3 shows a third embodiment of the glazing,

Figures 4a to 4c show a first embodiment of the lighting unit,

Figures 5a to 5c show a second embodiment of the lighting unit,

Figures 6a and 6b show a third embodiment of the lighting unit, and

Figures 7a and 7b show a fourth embodiment of the lighting unit.

Figure 1 shows a first embodiment of a glazing 10 consisting of a first layer (A) 1 which is at least partially covered by a luminous coating 12. The first layer (A) 1 is optically transparent and is preferably a glass produced in a float glass process. Thus, the first layer (A) 1 has a tin-side 14, which has been in contact with molten metal during the production of the first layer, and an air-side 13. The air-side 14 of the first layer (A) 1 is in direct contact with the luminous coating 12.

The luminous coating may cover the complete surface of the air-side 14 of the first layer (A) 1 , i.e. 100% of the area of the first layer (A) 1 . However, it is also possible that only a part of the surface of the first layer (A) 1 is covered by the luminous coating 12. The luminous coating 12 may be uniformly applied to the first layer (A) 1. Alternatively, the luminous coating 12 may be selectively applied so that certain patterns and/or shapes such as letters or images are formed. The luminous coating 12 preferably comprises at least one inorganic luminescent colorant embedded in a matrix material, wherein the matrix material is a glass. Further, the luminous coating 12 may be at least partially embedded in the first layer (A) 1 . For example, at least parts of the luminous coating may diffuse into the first layer (A) 1 or the first layer (A) 1 may be softened or partially melted in a heat treatment so that at least parts of the luminous coating 12 may be embedded into the material of the first layer (A) 1 . Figure 2 shows a second embodiment of a glazing 10 consisting of a composite structure of laminated layers 1 1 comprising in this order a first layer (A) 1 , an interlayer (C) 3 and a second layer (B) 2. The first layer (A) 1 is optically transparent and is preferably a glass produced in a float glass process. Thus, the first layer (A) 1 has a tin-side 14, which has been in contact with molten metal during the production of the first layer, and an air-side 13.

The second layer (B) 2 is may be optically transparent or opaque and may for example be based on a polymer or a glass. In the embodiment shown if figure 2, the second layer (B) 2 is a material obtained in a float glass process and has a tin-side 13' and an air-side 14'.

In the glazing 10 the luminous coating 12 is directly applied to the air-side 14 of the first layer (A) 1. The air side of the first layer (A) 1 , which carries the luminous coating 12, is laminated to a first side of the interlayer (C) 3. The air-side 14 with the luminous coating 12 may optionally be treated with an adhesion promoter. A second side of the interlayer (C) 3 is in direct contact with a first side of the second layer (B) 2 which may optionally be treated with an adhesion promoter. If the second layer (B) 2 is, as shown in figure 2, obtained in a float glass process, it is preferred to laminate the air-side 14' of the second layer (B) 2 to the second side of the interlayer (C) 3.

Figure 3 shows a third embodiment of a glazing 10 comprising the composite structure of laminated layers 1 1 as described with respect to figure 2. The sandwich structure of the glazing 10 of figure 3 comprises in this order a first support layer 16, a first additional interlayer 15, the composite structure of laminated layers 1 1 , a second interlayer 17 and a second support layer 18. The composite structure of laminated layers 1 1 comprises in this order the first layer (A) 1 , the interlayer (C) 3 and the second layer (B) 2, wherein the luminous coating 12 is applied to the air-side 14 of the first layer (A) 1 .

The support layers 16 and 18 may be used to provide additional strength and stability to the glazing 10 as required by the individual application.

In figures 4a to 4c a first embodiment of a lighting unit according to the present invention is shown. Figure 4a shows a side view, wherein X and X' identify the viewing direction of figure 4b and Y is a detail shown in figure 4c. The lighting unit comprises a glazing 10 with a first layer (A) 1 . The first layer (A) 1 is produced in a float glass process and has a tin-side 13 and an air-side 14. The air-side 14 is at least partially coated with a luminous coating 12. Figure 4b shows a cross sectional view of the lighting unit according to figure 4a. In the first embodiment, a plurality of light sources 4 is used. The light sources 4 are arranged such that the main direction 5 of the light beams emitted from the light sources 4 is directed onto the glazing 10. Figure 4c shows detail Y as marked in figure 4a. As can be seen in figure 4c, the light source 4 is arranged at half the height of the glazing 10. The light emitted by the light source 4 is coupled into the first layer (A) 1 . In further embodiments, the light source 4 may be shifted so that the main direction 5 of the light beams emitted from the light source 4 is directed into the luminous coating 12. Further, the half-value angle 6 of the light emission of light source 4 is marked.

Light emitted by light source 4 is coupled into the first layer (A) 1 and transmitted inside the first layer (A) 1 by total internal reflection. A part of the transmitted light is absorbed by the luminous coating 12. The luminous coating re-emmits light in an omnidirectional manner (at arbitrary angles), so that the luminous coating 12 scatters the light of light source 4. One direction of the scattered light is marked by reference numeral 7 in figure 4c.

In figures 5a to 5c a second embodiment of a lighting unit according to the present invention is shown. The second embodiment of the lighting unit comprises an additional optical element 8 which is arranged between the light source 4 and the glazing 10. In the shown embodiment the optical element 8 is a cylindrical lens.

In figures 6a and 6b a third embodiment of a lighting unit according to the present invention is shown. The glazing of the lighting unit shown in figures 6a and 6b is constructed as a sandwich structure comprising in this order the first layer (A) 1 , an interlayer (C) 3 and a second layer (B) 2. The first layer (A) 1 is at least partially coated with the luminous coating 12. The luminous coating 12 is applied to the air-side 14 of the first layer (A) 1 , see figure 2, and faces the interlayer (C) 3.

The third embodiment of the lighting unit comprises light sources 4 which are arranged on two opposing edges of the laminated glazing.

In figures 7a and 7b a fourth embodiment of a lighting unit according to the present invention is shown. The structure of the glazing 10 is identical to the structure described with respect to the third embodiment of the lighting unit of figures 6a and 6b. The fourth embodiment of the lighting unit comprises a profile 9. The profile 9 fixes the position of light sources 4, to the position optical element 8 and of the laminated layers 1 , 2 and 3 to each other. List of reference numerals

1 first layer (A)

2 second layer (B)

3 interlayer (C)

4 light source

5 main direction of the light beams emitted from the light source

6 angle of radiation (half-value angle)

7 one direction of light beams emitted from luminous particles 8 optical element

9 profile

10 glazing

1 1 composite structure of laminated layers

12 luminous coating

13 tin-side

14 air-side

13' tin-side (second layer)

14' air-side (second layer)

15 first additional interlayer

16 first support layer

17 second additional interlayer

18 second support layer