Illuminable enamelled substrate and its manufacture

Abstract

The invention relates to an illuminable enamelled substrate (and its manufacture) with a first glass sheet (1) comprising a discontinuous scattering layer in enamel, in a vitreous binder and microcrystals.

Description

[0001] DESCRIPTION

[0002] TITLE: ILLUMINABLE ENAMEL SUBSTRATE AND ITS MANUFACTURE

[0003] The invention relates to the field of enameled substrates used to form luminous glazed devices by means of a light source.

[0004] Inorganic light-emitting diodes are used to produce luminous glazing, particularly for vehicles. The light emitted by the diodes is introduced through the edge into the glazing forming a guide, the light being extracted from the glazing by a diffusing layer on the glazing, defining the luminous surface. The diffusing layer is conventionally a diffusing enamel obtained by screen printing containing dielectric diffusing particles such as alumina particles dispersed in the vitreous matrix. This is for example a flat area of ​​enamel or a set of screen-printed enamel spots at least 300 pm wide, taking into account the resolution of the screen printing dictated by the size of the openings of the screen printing screens. This luminous glazing has a very cloudy appearance in the area of ​​the diffusing layer. The light transmission of the enamel is less than 40%, the haze is 90 to 100%.

[0005] The present invention therefore sought to develop an alternative diffusing layer further increasing transparency in the off state while still being capable of extracting light.

[0006] To this end, the invention has as its first object an enamelled substrate in particular for a luminous glazed device (of a vehicle in particular land, sea, rail, or air or even building or street furniture), comprising a first sheet of glass (preferably clear or extra-clear, in particular colorless, and preferably soda-lime-silica, in particular with a refractive index nO at 550nm of 1.4 to 1.6, in particular with a thickness of at most 10mm and even at most 5 or 3mm and preferably at least 0.1mm, 0.3mm or 0.7mm.

[0007] The diffusing layer comprises at least one first diffusing pattern preferably with a width of at least 0.1 mm and even at least 0.5 mm or even 1 mm, in particular with a length of at least 0.6 or 1 mm and even 1 cm, and with a surface area S0 in particular of at least 100 pm by 600 pm.

[0008] The first glass sheet comprises on (directly or on a sub-layer) a (single) first main face (tin face or opposite face if float glass) a diffusing layer of diffusing enamel comprising a vitreous matrix including a vitreous binder (preferably vitrocrystalline in a vitreous binder with (micro)crystals generated -in situ- during firing with or without growth germs). The vitreous matrix is ​​vitrocrystalline thus comprising microcrystals in a vitreous binder, the microcrystals being diffusing and in that the first diffusing pattern is discontinuous.

[0009] The diffusing layer preferably comprises a weight content of coloring additives of at most 10% of the total weight of the enamel.

[0010] The first diffusing pattern may comprise either a set of disjointed micro-spots of said diffusing enamel or a continuous enamel area with through holes.

[0011] The diffusing layer is discontinuous: preferably in one configuration it forms a set of disjointed micro-plots (and without a continuous area of ​​enamel layer). or in an alternative configuration it comprises a continuous area with holes of submillimeter width, at least 10 pm (and possibly comprises enamel micro-plots in the holes) with higher blur and lower transparency than in the other configuration.

[0012] In one configuration, the first diffusing pattern (and even one or more other diffusing patterns of the diffusing layer) comprises a set of micro-plots disjointed from said diffusing enamel - or even consists of said set of disjoint micro-plots. Between the micro-plots (defining an inter-plot zone), the first sheet is preferably transparent (devoid of layered enamel, for example extending over at least 100 μm), the first main face preferably being bare or with the underlayer.

[0013] The microplots (all or part) can be of various shapes, having an irregular contour base (notably with a degree of circularity detailed later), and / or distributed in an irregular or even random manner.

[0014] By defining within the first diffusing pattern an analysis surface S1 less than S0, and S1 being at least 50pm by 50pm and at most 100pm by 600pm - for example 500pm*340pm-, and a surface S2 which is the sum of the surfaces of the microplots in this surface S1:

[0015] - the first diffusing pattern is defined by an equivalent average diameter Am (with microplots having a base reduced to a circle) of said microplots less than 10 pm or less than or equal to 5 pm and at least 1 pm

[0016] - the first diffusing pattern is defined by an average distance Bm between neighboring microplots and Bm / Am ranging from 0.3 to 2 or even to 1.5

[0017] - preferably the first diffusing pattern comprises a coverage rate Tm of said microplots which is the surface S2 divided by the surface S1, Tm is less than 50%, and even 45%, 40%, 35% or 30% and preferably at least 5%, 8%, 10%, 11%, 15%, Preferably the arrangement of microplots can be further defined by at least one of the following characteristics:

[0018] - the average distance Bm is less than 5pm, 4pm, or 3pm and better at least 1pm,

[0019] - in said analysis surface, the first diffusing pattern is defined by an average perimeter Pm (preferably taken at the base) of at least 3pm or 4pm and preferably less than 10pm

[0020] - in said analysis surface, the first diffusing pattern is defined by an average circularity Cm (preferably taken at the base) of at least 0.7 or 0.75, 0.8, or 0.85 and less than 1 or 0.95 and

[0021] - at least for the first diffusing pattern and preferably for the diffusing layer as a whole (first diffusing pattern and one or more other diffusing patterns), the microplots (all or part) have a thickness of at most 4.5 pm, 4 pm or 3.5 pm or 3 pm and at least 0.5 pm or 1 pm.

[0022] - at least in said analysis surface and preferably for the diffusing layer as a whole (first diffusing pattern and one or more other diffusing patterns), the microplots with a width (taken at the base) greater than 1 pm have a thickness of at least 0.5 pm or 1 pm.

[0023] - at least in said analysis surface and preferably for the diffusing layer as a whole (first diffusing pattern and one or more other diffusing patterns), the first diffusing pattern comprises among the microplots (called primary) plots with a diameter of 1 pm to 20 pm or 10 pm and plots (called secondary, more numerous than the primary plots) with a diameter of less than 1 pm and at least 0.1 pm, in particular at least 70%, 80% or 90% of the microplots (in number) have a diameter of at most 20 pm or 15 pm or 10 pm or 5 pm,

[0024] - at least in said analysis surface and preferably for the diffusing layer as a whole (first diffusing pattern and one or more other diffusing patterns), the microplots have a curved surface in particular with an average contact angle of less than 160° or 120° and even greater than 60°.

[0025] With such an arrangement of studs, a substrate is obtained provided with one or more transparent patterns which do not significantly degrade the light transmission and with a reduction in haze, compared to a solid, continuous diffusing layer. Use as automotive glazing, side glazing, rear window, glass roof, etc. is perfectly feasible. The first diffusing pattern alone or with one or more diffusing patterns formed for the diffusing layer are capable of extracting the light from the first glass sheet forming a light guide coupled to a light source.

[0026] In the case of a plurality of diffusing patterns, by using enamels of various natures and / or thicknesses, therefore with different levels of transmission (semi-transparent, translucent) and / or various arrangements of studs (by adjusting the process parameters and / or the enamel paste), and the invention makes it possible to obtain glazing capable of illuminating differently simultaneously, or sequentially, in particular with more or less transparency.

[0027] With light sources (visible and even ultraviolet LIV) of various types, or even luminescent particles of various types, the invention makes it possible to obtain glazing capable of illuminating differently or even in several colors, simultaneously or sequentially.

[0028] In the most conventional configuration, the enameled substrate is monolithic or part of a laminate and / or double glazing so as to preserve transparency (an object can be seen behind the diffusing layer or to see the outside, the sky for a vehicle roof). However, one may want the enameled substrate with the diffusing layer to be as invisible as possible in the off state and assembled with an additional opaque sheet or with an opaque layer behind this diffusing layer. The diffusing layer may comprise the first diffusing pattern alone or with one or more other diffusing patterns each with an arrangement of micro-plots identical to that described or similar while keeping the parameters Am, Bm, Bm / Am, Cm and their numbering. Another diffusing layer may coexist in the form of a flat area of ​​enamel preferably occupying less than 10% of the transparent area of ​​the first sheet.

[0029] The diffusing layer of enamel is for example in contact with the first main face. A transparent sub-layer (single or multi-layer), preferably mineral, at least resistant to enamel firing, and even with a thickness of at most 1 pm or 0.2 pm can be provided between the diffusing layer and the first face, as long as the latter does not disturb the guidance and / or extraction of light.

[0030] The vitreous matrix is ​​vitrocrystalline, the microplots thus contain microcrystals (generated during cooking and not by adding particles to the liquid composition) in particular diffusing in a vitreous binder (with molten glass frit).

[0031] Microcrystals contain all or part of the elements of the vitreous binder, elements in the oxidized state. Microcrystals are defined compounds. Microcrystals are in the vitreous binder or on the surface, in particular present in so-called primary plots of at least 1 pm - in dendritic, needle-like form. Microcrystals are of various shapes: non-calibrated, non-spherical, rather elongated.

[0032] These microcrystals provide the advantage of diffusing light and can replace all or part of the so-called additional diffusing elements added to the binder such as metal oxide pigments (white, colored, distinct from black, etc.).

[0033] The vitreous binder may preferably be dense or low porous, comprising gas or void porosities which may be part of diffusing elements with added microcrystals and / or diffusing particles (white or colored pigments).

[0034] The glass-crystalline matrix may be a (transparent), preferably colorless matrix, in particular the volume fraction of glassy binder being at least 80, 85 or 90% of the volume of the enamel and the remainder for microcrystals and / or other diffusing particles.

[0035] Preferably, for the vitreous binder, it is preferable to avoid lead, cadmium, and mercury oxide. It is preferable to avoid (or have a weight content of less than 1% of the total weight of the enamel) transition metal oxides from columns 5 to 11 and even 12 - except zinc - of the periodic table of elements. The total content of alkali oxides other than Na2O (such as O2O, K2O) for the vitreous binder is preferably at most 3% by weight of the vitreous binder (and even of the enamel), in particular 2% and even 1% or 0.5%. In one case, the only alkali oxide present is advantageously Na2O. The weight content of cumulative oxides of alkaline earth metals Mg, Ca, or even Mg, Ca and Ba can be limited to 5%, 2%, 1% or 0.5% by weight of the vitreous binder (and even of the enamel).

[0036] Furthermore, in a first embodiment, cumulatively:

[0037] - for the vitreous binder, the weight content of silica SiO2 is the highest,

[0038] -- the weight content of lead oxide PbO is at most 0.5% of the total weight of the vitreous binder (respectively of the enamel) and better is zero, and also the weight content of cadmium, mercury or chromium oxide is zero.

[0039] The vitreous binder and / or the microcrystals of the glass-crystal matrix may contain oxides of at least the following elements: Si, Bi, Na, Zn, Ti, Al, B. The vitreous binder and / or the microcrystals of the glass-crystal matrix may be based on bismuth and / or zinc silicate or bismuth and / or zinc borosilicate.

[0040] Preferably, regarding the constitution of the diffusing layer, one or more of the following alternative or cumulative characteristics are provided:

[0041] - the weight content of the vitreous binder is at least 80% or at least 90% of the total weight of the enamel

[0042] - the enamel has a weight content of impurities of at most 0.5% of the total weight of the enamel - the total weight content of coloring elements (Fe2C>3, CuO, CoO, Cr2Os, MnO2, Se, Ag, Cu, Au, Nd2Os, Er2Os) is at most 0.5% and even 0.1% of the total weight of the vitreous binder and even of the vitreous matrix and preferably zero (except for unavoidable impurities) so that the enamel is colorless or as little colored as possible

[0043] - the weight content of coloring additives such as pigments (metal oxide) - black or white, even colored - is preferably at most 5% or 1% of the total weight of the enamel, in particular 0.5% and even 0.1%, or even zero.

[0044] The enamel is preferably translucent, colorless or colored, whitish or with another color (without being completely opaque).

[0045] We strongly limit and better avoid coloring additives such as a metallic oxide pigment (mixed).

[0046] We can strongly limit and even avoid:

[0047] - one or more fillers such as silica and alumina quartz, refractory oxide fillers such as boro-alumina silicates, alumina silicates, calcium silicates, sodium-calcium-alumina silicates, wollastonite, feldspar,

[0048] - and / or other conventional additives, such as iron, silicon, zinc and the like, titanates.

[0049] Traditionally, the main faces of laminated glazing (automotive or building) are numbered from 1 to 4:

[0050] - face F1 is the external (outer) face of the exterior glass, preferably tinted in automobiles and

[0051] - face F2 is the internal face (lamination interlayer side) of the outer glass; the lamination interlayer is preferably PVB or EVA

[0052] - face F3 is the internal face (lamination interlayer side) of the interior glass, preferably colorless, often of thickness less than or equal to that of the exterior glass

[0053] -- face F4 is the internal face (cabin or living area side) of the interior glass

[0054] The enamel can be semi-transparent (whitish in particular with little or no pigment).

[0055] The enamel can be less transparent or even opaque when the first face is opposite the observation face of the light diffusing pattern, in particular:

[0056] - the first face is face F1 and the observation face is face F2 (or the other way around if you want a pattern visible on the outside)

[0057] - or the observation face is face F4 if the first sheet is the internal glass of a laminated glazing or within the laminated glazing (internal guide).

[0058] The enamel is translucent (the first face is opposite the observation face of the light pattern, in particular F2 or F4 if laminated). The microcrystals can occupy a more or less significant volume fraction of the microplots, for example at most 60% within the microplot, in particular the so-called primary microplots with an equivalent diameter of at least 1 pm. The size of the microcrystals (equivalent diameter) is smaller than the size (thickness and / or equivalent diameter) of the microplots. There may be disjointed microcrystals within the microplots (for example at least 5), in particular the so-called primary microplots with an equivalent diameter of at least 1 pm. They can emerge or remain within the microplots.

[0059] The microcrystals are preferably with a diameter, for example equivalent, (D50 or D90 in particular) of at least 0.1 pm for example less than 2 pm and even 1 pm.

[0060] The microcrystals and / or other diffusing particles may occupy a more or less significant volume fraction of the microplots, for example at most 60% within the microplot, in particular the so-called primary microplots with an equivalent diameter of at least 1 pm.

[0061] The diffusing layer may optionally include particles (inorganic, refractory, in particular oxides), in particular diffusing particles which may be crystallized, additional (because added to the liquid composition), dispersed in the vitreous matrix. These particles are detectable by X-ray diffraction (known as "XRD").

[0062] These diffusing particles (distinct from possible growth germs) are not necessary or are in reduced quantity to reinforce diffusion.

[0063] The diffusing particles are preferably with a diameter (D50 or D90 in particular) of at least 0.1 pm, for example less than 2 pm and even 1 pm.

[0064] The diffusing particles are for example solid and even possibly hollow particles for example hollow silica - The diffusing particles (non-luminescent) are chosen for example from particles of alumina, zirconia, silica, titanium dioxide, calcium carbonate, barium sulfate and in particular they are pigments (white).

[0065] The diffusing layer may optionally also comprise luminescent diffusing particles alone or in combination with the added diffusing particles.

[0066] The diffusing layer (may comprise a volume fraction of diffusing porosities of at most 10% or 5% or 1% of the volume of the enamel (in the first diffusing pattern.

[0067] The diffusing layer may have a weight content of diffusing particles (additional, possibly added apart from crystallization seeds in the glass-crystal matrix) of at most 10% or 5% or 1% of the total weight of the enamel and even down to 0%. The size of the diffusing particles (equivalent diameter), other than the microcrystals, is smaller than the size (thickness and / or equivalent diameter) of the microplots. There may be disjoint diffusing particles within the microplots (for example at least 5), in particular the so-called primary microplots with an equivalent diameter of at least 1 μm. They may emerge or remain within the microplots.

[0068] In one embodiment, the diffusing layer comprises at most 5% by weight of (inorganic) luminescent particles. The luminescent particles are dispersed in the vitreous binder of the glass-crystalline matrix.

[0069] When the diffusing layer comprises luminescent particles, preferably a light source is added, such as a light-emitting diode (LED), emitting light of a wavelength at which the luminescent particles are excited and re-emit light radiation in the visible range. This or these LEDs can be positioned as LEDs emitting in the visible range. This excitation wavelength is for example in the UV, particularly UVA, and even 365 to 400 or 390 nm. LEDs emitting both at this excitation wavelength and in the visible range could be envisaged.

[0070] By using diffusing particles of various types, and / or light sources of various types, or even luminescent particles of various types, the invention makes it possible to obtain glazing capable of illuminating in several colors, simultaneously or sequentially.

[0071] The diffusing patterns can have various shapes, symmetrical or asymmetrical. The distribution of the diffusing patterns on the substrate can be periodic or aperiodic. A periodic distribution means that the diffusing patterns are placed on the first glass sheet in an orderly manner while an aperiodic distribution means that the diffusing patterns are placed on the first glass sheet in a random manner. The diffusing patterns can have any shape and be more or less large. However, it may be desired that the diffusing layer extends over a region of the first main face, for example, extends over at most 50%, 40% or 30% or 20%, 10% 1%, 0.1% of the first face.

[0072] The diffusing layer can be distributed over the entire transparent area, even to the point of being adjacent to an opaque (border) area such as the masking frame. For example, the diffusing layer is local, on the periphery of the first face.

[0073] The diffusing layer may cover less than 50% of the surface of the first glass sheet when it is necessary to maintain the most transparent window clear possible in the off state. A luminous peripheral band may be formed along a lateral or longitudinal edge, lower or upper, of the first glass sheet.

[0074] The luminance is preferably at least 1 Cd / m 2 .

[0075] The diffusing layer can be spaced at least 10mm or even 40mm from the light injection zone (wall of a hole in the first sheet, edge, edge of the light redirection element). We can therefore have a transparent zone of width of at most 40mm between the injection zone and the nearest edge of the diffusing layer.

[0076] The first sheet of glass (preferably extra-clear glass) with the diffusing layer preferably has:

[0077] - a light transmission factor of at least 70%, 75%, 80%, 85% and even at least 90% preferably within the meaning of standard EN 410:1998,

[0078] - a blur (in transmission) of at most 80% and even at most 20% or 15% or 5%

[0079] - and preferably an image sharpness (clarity in English) of at least 80%, 90%, 95%. In particular, the first glass sheet (preferably extra-clear glass) with the diffusing layer preferably has:

[0080] - a light transmission factor of at least 70% or 75%, and a haze (in transmission) of at most 80% or 70%

[0081] - a light transmission factor of at least 80%, and a haze (in transmission) of at most 55%

[0082] - a light transmission factor of at least 85%, and a haze (in transmission) of at most 30%

[0083] - a light transmission factor of at least 90%, and a haze (in transmission) of at most 6%.

[0084] Advantageously, the blur is at most 30%, the sharpness at least 90% or 95%, the light transmission factor is at least 88%.

[0085] In one embodiment, when measuring blur, the light spot is centimetric at the surface of the diffusing layer, in particular at most 5 cm, in particular approximately 2.6 cm, and in the area illuminated by the spot the diffusing layer (with the first diffusing pattern) preferably occupies at least 30%, 50%, 60% of the spot.

[0086] The light transmittance factor TL can be calculated using illuminant D65, the measurement being made for example using a spectrophotometer equipped with an integrating sphere, the measurement at a given thickness then being converted if necessary to the reference thickness of 4mm according to standard EN 410:1998. The haze and even the sharpness are preferably measured by a Hazemeter (such as BYK-Gardner Haze-Gard Plus) preferably according to standard ASTDM D1003 (without compensation).

[0087] It is preferable to carry out the measurements before any possible lamination. For example, the illuminant is placed on the opposite side to the first supporting side of the diffusing layer.

[0088] Furthermore, the diffusing layer may have a brightness in terms of brightness unit (ub) of at least 60 or 80 and better still at least 100, reflecting a smooth surface. The diffusing layer is preferably a monolayer (obtained by depositing a single layer based on glass frit).

[0089] Furthermore, the glass with the diffusing layer (the first pattern) can have a clarity L* of at most 60 and even at most 40 or 30.

[0090] Furthermore, the glass with the diffusing layer (the first pattern) can have an optical density of at most 0.4 and even at most 0.2.

[0091] The thickness (or maximum height) of the microplots can be determined by observation in section view of the scattering layer under a scanning electron microscope at a magnification of 250 times (for example with a voltage of 20KV).

[0092] The parameters Am, Bm, Tm, Cm, Pm can be determined from the processing and analysis of black and white SEM images of the surface under a scanning electron microscope at a magnification of 250 times.

[0093] For the SEM image, we choose CBS (Concentric Backscattered) mode. CBS is a backscattered electron detector that produces chemical contrast images. For example, the software called Image J is used for processing and analyzing SEM images.

[0094] For each SEM image, a SEM image threshold is set from 90 to 255, so a threshold is set from which any pixel with an intensity greater than or equal to the threshold is assigned the value 255 and the rest of the pixels will be at 0.

[0095] We choose the surface S1 for example 500pm by 340pm within the first diffusing pattern.

[0096] All particle sizes are taken into account by default as well as all circularities.

[0097] The number of isolated plots is counted and the parameters Am, Bm, Tm, Cm, Pm are measured.

[0098] The evaluation can be repeated in several regions of the first scattering pattern or even in several scattering patterns for an even more representative calculation of the parameters.

[0099] Preferably, the arrangement of microplots can be further defined by at least one of the following characteristics: - the average distance Bm is less than 5 pm, 4 pm, or 3 pm and better still at least 1 pm,

[0100] - in said analysis surface, the first diffusing pattern is defined by an average perimeter Pm (preferably taken at the base) of at least 3pm or 4pm and preferably less than 10pm

[0101] - in said analysis surface, the first diffusing pattern is defined by an average circularity Cm (preferably taken at the base) of at least 0.7 or 0.75, 0.8, or 0.85 and less than 1 or 0.95.

[0102] Alternatively or cumulatively (with two diffusing patterns) the discontinuous enamel layer (at least the first diffusing pattern) may comprise a continuous enamel area having disjointed (micrometric) openings (through holes). The openings may be irregularly shaped and / or irregularly distributed.

[0103] By defining within the first diffusing pattern said continuous enamel zone with openings, an analysis surface S'1 less than S0, and S'1 being at least 50pm by 50pm and at most 100pm by 600pm - for example 500pm*340pm-, and a surface S'2 which is the sum of the surfaces of the openings in this surface S'1

[0104] - the first diffusing pattern is defined by an equivalent average diameter A'm (with openings having a base reduced to a circle) of said openings less than 20pm or 10pm and even at least 1pm

[0105] - the first diffusing pattern is defined by an average distance Bm between said neighboring openings at 20pm or 10pm of at least 1pm

[0106] - preferably the first diffusing pattern comprises a coverage rate T'm of said openings which is the surface S'2 divided by the surface S'1, T'm is less than 50%, and even 45%, 40%, 35% or 30% and preferably at least 5%, 8%, 10%, 15%.

[0107] The A'm, B'm, T'm, and white parameters of the surface under scanning electron microscope at 250 times magnification.

[0108] For the SEM image, we choose the CBS (Concentric Backscattered) mode. The CBS is a backscattered electron detector that produces chemical contrast images. For example, we use the software called Image J for SEM image processing and analysis. For each SEM image, we perform a SEM image threshold from 90 to 255, so we set a threshold from which any pixel with an intensity greater than or equal to the threshold is assigned the value 255 and the rest of the pixels will be at 0. We choose the surface S'1, for example 500pm by 340pm within the first scattering pattern. All aperture sizes are taken into account by default as well as all circularities. We count the number of apertures and we measure the parameters A'm, B'm, T'm. The first sheet of glass can have rectangular, square or even any other shape (round, oval, polygonal) main faces.The glass sheet can be larger than 1.5 m. 2 .

[0109] The glass of the first glass sheet (and even of the other possible glass sheet(s)) is preferably of the float type. In this case, the diffusing layer can be deposited on the "tin" side as well as on the "atmosphere" side of the substrate. Other characteristics can be provided for the first glass sheet:

[0110] - the first sheet of glass is curved or even tempered.

[0111] - the first glass sheet is tempered, in particular thermal tempering (after firing in a tempering furnace, rapid cooling by nozzles typically), firing in the tempering furnace can be used to form the enamel layer from a liquid composition (paste) - possibly with prior drying - based on glass frit

[0112] For a roof (often tinted), we prefer a non-zero light transmission TL and even at least 0.5% or at least 2% and at most 40% and even at most 8%.

[0113] It may be desired that the diffusing layer forms a light marker, one or more light signals. In the present application, the term signaling is based on iconic and / or linguistic semantics, i.e. using signs (numbers, pictograms, logos, symbolic colors, etc.) and / or a letter or words. In one embodiment, the surface of the diffusing layer may be a free surface (no other element(s) on it).

[0114] This can be the F4 face of a laminated glazing or the F1 or F2 face of a monolithic glazing alone or even the external or internal face of a glazing of a double glazing In one embodiment, the first sheet of glass is monolithic which is possibly part of a double glazing the diffusing layer has a free surface or covered by a functional element.

[0115] The functional element is optionally transparent, preferably with a thickness of at most 1.5 mm or submillimeter, in particular:

[0116] -a polymeric film in adhesive contact with the diffusing layer

[0117] -and / or a functional overlayer (single-layer or multi-layer).

[0118] It can be a film glued with an optical glue on the first main face and in particular the enamelled substrate is a monolithic glazing (not part of a laminated or multiple glazing.

[0119] The polymeric film may be tinted and / or may carry a functional layer (electroconductive, low emissivity, heating, etc.). Alternatively, the tinted polymeric film, carrying a functional layer, is bonded to the second main face. The polymeric film may have a thickness of between 5 μm and 1 mm, preferably at least 50 μm and at most 200 μm. The polymeric film may be chosen from a polyester, in particular a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN), a polycarbonate (PC), a polyolefin such as a polyethylene (PE), a polypropylene (PP), a polyurethane, a polyamide, a polyimide.

[0120] PET is preferred due to its transparency, surface quality, mechanical strength, and availability in all sizes. The absorption of this transparent film, particularly PET, is preferably less than 0.5% or even at most 0.2%, and with a haze of less than 1.5% and even at most 1%. The optical adhesive is in particular (a resin) based on polyester, acrylic, or silicone. It may be a pressure-sensitive adhesive (PSA). In one embodiment, the first glass sheet is part of a laminated glazing unit (possibly curved) comprising:

[0121] - said first sheet, in particular colorless, made of clear or extra-clear glass

[0122] - a lamination interlayer, in particular colorless or tinted

[0123] - and a second transparent, colorless or tinted sheet, preferably made of clear or extra-clear glass or tinted glass or a plastic such as poly(methyl methacrylate PMMA or polycarbonate PC).

[0124] Preferably, the first main face is on the lamination interlayer side, the diffusing layer being in adhesive contact with the lamination interlayer or covered (on) by a functional element possibly in adhesive contact with the lamination interlayer.

[0125] Preferably, the laminated glazing comprises a light source, such as a light-emitting diode (LED). The LED(s) may be in or near a (through) hole in the inner glass sheet for optical coupling through the wall delimiting the hole, or opposite the edge of the inner glass sheet.

[0126] The enamelled substrate may therefore further comprise a light source, in particular a plurality of inorganic light-emitting diodes, which is optically coupled to the first glass sheet forming a light guide, in particular injection of light from the light source by a slice of the first glass sheet or a wall of a hole in the first glass sheet or by the first main face or a second main face opposite the first main face, in particular direct optical coupling or by means of an optic, in particular a light redirection element on the first or second main face and offset from the diffusing layer.

[0127] The first sheet of glass may be monolithic which may be part of double glazing; the diffusing layer has a free surface or one covered by a functional element comprising a film and / or a coating (in particular a functional element in contact with the diffusing layer and in particular in the inter-plot zone between the microplots in contact with the first bare face or with an underlayer as already described).

[0128] The first sheet of glass can be part of a laminated glazing comprising:

[0129] - said first sheet, preferably made of clear or extra-clear glass

[0130] - a lamination interlayer preferably in PVB, possibly tinted

[0131] - and a second transparent sheet of glass or plastic, preferably tinted, preferably the first main face is on the lamination interlayer side, the diffusing layer being in adhesive contact with the lamination interlayer or covered by a functional element (in particular a functional element in contact with the diffusing layer and in particular in the inter-plot zone between the microplots in contact with the first bare face or with an underlayer as already described) preferably in adhesive contact with the lamination interlayer.

[0132] The first sheet is the internal glazing and preferably the first main face is the internal face called face F3 or the first sheet is between the second transparent sheet and a third sheet of glass (forming an internal light guide, within the lamination interlayer).

[0133] The laminated glazing may include a functional element, in particular a transparent one, chosen from one or more of the following elements:

[0134] - a layer of silica, particularly porous and for example sol-gel, forming an anti-reflective layer

[0135] - a masking layer possibly adjacent to the diffusing layer, in particular peripheral, in particular an enamel layer

[0136] - an electrically conductive layer, in particular an electrode, an electrical supply layer for (opto)electronic components or a heating layer, in particular a layer of transparent conductive oxide, in particular within the laminated glazing

[0137] - a solar control (and / ) or low emissivity layer, in particular a coating on the F4 face comprising a functional layer of transparent conductive oxide or a metallic functional layer within the laminated glazing

[0138] - within the laminated glazing (between the faces F1 and F4), an electrically controllable device, in particular with variable diffusion and / or tint, in particular with liquid crystals or electrochromic, or an optical valve (SPD for suspended particle device in English) or a multipixel screen (with liquid crystals, active matrix OLED, etc.), for example as described in patent application WO2017 / 115036, or an additional light element, an electrically controllable device offset or opposite the diffusing layer, - a low-index optical isolating element with a refractive index lower than the refractive index of the first glass sheet, between the first face and the second tinted glass sheet, in particular between the first face and the tinted lamination interlayer, in particular a porous silica layer on the first face or a fluorinated film, in particular chosen from ethylene tetrafluoroethylene (ETFE), fluorinated ethylene-propylene copolymers (FEP).

[0139] A sol-gel porous silica layer with a refractive index of at most 1.3, even at most 1.2, and better still with a thickness of at least 200nm, even at least 400nm, and preferably at most 1 pm, is described in application WO2008 / 059170, in particular in figure 11, or even in application WO2015 / 101745.

[0140] In an exterior light configuration, the first glass sheet may be the external glazing and preferably the first main face is the internal face called face F2.

[0141] In one configuration the enamelled substrate forms a glazing for a land, water or air vehicle, or as building glazing, in particular:

[0142] - a laminated, curved roof, the first sheet of glass is the internal glazing or between a second sheet of glass and a transparent sheet of glass or polymer

[0143] - a window, in particular the first sheet of glass is the external glazing, the diffusing layer is on the passenger compartment side

[0144] - a side (window), laminated or monolithic, the first sheet of glass is the internal or external glazing

[0145] - a laminated, curved windshield, the first sheet of glass is the internal or external glazing.

[0146] We prefer to choose a lamination interlayer (clear or tinted) that is as blurry as possible, i.e. at most 1.5% and even at most 1%.

[0147] These interlayers may be based on polymers chosen from polyvinyl butyral (PVB), polyvinyl chloride (PVC), polyurethane (PU), polyethylene terephthalate or ethylene vinyl acetate (EVA). The interlayers preferably have a thickness of between 100 μm and 2.1 mm, preferably between 0.3 and 1.1 mm. The lamination interlayer may be made of polyvinyl butyral (PVB), polyurethane (PU), ethylene / vinyl acetate copolymer (EVA), formed from one or more films, for example having a thickness of between 0.2 mm and 1.1 mm. A conventional PVB such as RC41 from Solutia or Eastman may be chosen.

[0148] The lamination interlayer may optionally be composite in its thickness (PVB / plastic film such as polyester, PET etc / PVB). The surface area of ​​the lamination interlayer may be less than the surface area of ​​the laminated glazing, for example leaving a groove (in a frame or strip), free and therefore not laminated.

[0149] For a laminated windshield, the lamination interlayer may have a cross-section that tapers to a wedge shape from the top to the bottom of the laminated windshield, particularly to avoid a double image in the case of an additional head-up display (HUD). The lamination interlayer may be acoustic.

[0150] The second sheet may be larger than the first, thus exceeding the latter over at least part of its perimeter, in particular when the first sheet is illuminated by its peripheral edge, the light source such as the LED modules may then rest on the face F2 of the second sheet, where it exceeds the first sheet.

[0151] As an example of offset or non-offset glazing, with edge-lit glazing, we can cite patent applications WO2010 / 049638, WO2013079832, WO2013153303.

[0152] The first sheet of glass may include a masking layer, often peripheral, on the first or second face, for example an opaque black or dark enamel layer forming a peripheral band or even a peripheral frame.

[0153] The diffusing layer can be more central, offset from the masking layer

[0154] The first glass sheet may in particular comprise a masking layer, in particular enamel, adjacent to the diffusing layer or on the second face offset from the diffusing layer, in particular a peripheral masking layer along the optical coupling edge with a light source.

[0155] Preferably, at least in the guiding zone, the width of this layer along the optical coupling edge (between the edge and the edge of the diffusing layer) is removed or limited to less than 5 cm or even 3 cm.

[0156] More broadly:

[0157] - the interior glazing (often the first sheet of glass) may have a peripheral interior masking layer (may be a layer of black or dark enamel, a layer of paint or opaque ink preferably on the F2 face or on the lamination interlayer or even on an additional carrier film (PET etc.).

[0158] - and / or the outer glazing (sometimes the first sheet of glass) may have a peripheral outer masking layer (respectively outer masking layer) which is a layer of black or dark enamel, a layer of paint or an opaque ink preferably on the F2 face (respectively F3 or F4) or on the lamination interlayer or even on an additional carrier film (PET etc). Advantageously, the inner and outer masking layers are made of the same material, preferably enamel, in particular black, or in F2 and F4 or in F2 and F3. The diffusing layer may be on the F3 face:

[0159] - in a saving of the inner masking layer on face F3 or face F4

[0160] - opposite the outer masking layer on face F2.

[0161] In the alternative embodiment (colorless outer glass, for example, glasses) the diffusing layer can be on the F2 side:

[0162] - in a saving of the outer masking layer on face F2

[0163] - and even opposite the inner masking layer opposite F3 or F4.

[0164] The first glass sheet may comprise under the diffusing layer and / or on a second main face opposite the first main face with the diffusing enamel layer and / or on the first face under the diffusing layer and / or adjacent to the diffusing layer, a transparent functional layer - as long as this layer does not significantly impair the light guide function (by its absorption, etc.).

[0165] There are several types of functional layers (on the first sheet of glass or in the laminated glazing) chosen from at least one of the following layers:

[0166] - a masking layer adjacent to the diffusing layer, in particular a peripheral layer, in particular an enamel layer, preferably less than 5 cm or 3 cm wide between the optical coupling edge and the nearest edge of the diffusing layer

[0167] - an electrically conductive layer, in particular an electrode (electroconductive layer connected to a power supply), a layer (forming a circuit) for the electrical supply of (opto)electronic components (sensors etc.) - components which are as transparent and / or discreet as possible, if possible -, in particular a layer of transparent conductive oxide,

[0168] - a layer of electromagnetic shielding

[0169] - a heating layer, i.e. an electrically conductive layer supplied electrically (typically by two current supply strips),

[0170] - a layer reflecting or absorbing solar radiation called a solar control (and / )or low emissivity layer, in particular a coating comprising (at least) a functional layer of transparent conductive oxide (TCO) or (at least) a metallic functional layer, a solar control layer also being able to serve as a heating layer with a current supply at the periphery.

[0171] The electrically conductive layer may comprise transparent conducting oxides (TCOs), i.e. materials that are both good conductors and transparent in the visible range, such as tin-doped indium oxide (ITO), antimony- or fluorine-doped tin oxide (SnO2:F) or aluminum-doped zinc oxide (ZnO:Al). The electrically conductive layer can also be a metallic layer, preferably a thin layer or a stack of thin layers, called TCC (for "Transparent conductive coating" in English) for example in Ag, Al, Pd, Cu, Pt In, Mo, Au and typically with a thickness between 2 and 50 nm. It is possible to use for example a polymeric film coated with an electrically conductive layer, for example a clear PET film called XIR from the company Eastman, a coextruded PET-PMMA film, for example of the SRF 3M® type (SRF for Solar Reflecting Film).

[0172] In a preferred embodiment in the case of laminated glazing (glass roof etc.):

[0173] - the first and / or second glazing is tinted and / or the lamination interlayer is tinted over all or part of its thickness

[0174] - the F4 face is coated with a layer of transparent electro-conductive oxide (called TCO) in particular a stack of thin layers with TCO layer

[0175] - and / or preferably the face F2 or F3 is coated with a stack of thin layers with silver layer(s).

[0176] The low-emissivity layer based on TCO can be cited as those described in patent LIS2015 / 0146286, on the F4 face, in particular in examples 1 to 3.

[0177] The light source preferably comprises a plurality of inorganic light-emitting diodes, although other types such as a light strip (OLED, etc.) may be considered.

[0178] The invention also relates to the use of laminated glazing obtained by a manufacturing process described above, as glazing for land, water or air vehicles, or as glazing for buildings, in particular as automotive glazing, especially as an automotive roof.

[0179] Thus, the invention also relates to the method of manufacturing the enameled substrate, in particular as described previously, which comprises, on a first main face of a first glass sheet, the formation of a diffusing layer of diffusing enamel comprising a vitreous matrix (diffusing layer comprising a first diffusing pattern with a width of at least 0.1 mm), involving in this order:

[0180] - a deposit on the first sheet of glass of a film of a vitrifiable liquid composition called enamel paste comprising a mixture of an organic medium and an inorganic solid comprising a glass frit with a given glass transition temperature Tg1,

[0181] - preferably drying (in particular by infrared or even ultraviolet) at a temperature of at most 200°C

[0182] - firing at a temperature Te above the glass transition temperature Tg1 of the glass frit to form the glass matrix. The glass frit is crystallizable and the enamel paste preferably contains growth nuclei, the firing generates the formation of a glass-crystalline matrix containing diffusing microcrystals and the diffusing layer is discontinuous.

[0183] Advantageously, the deposit is by screen printing.

[0184] The firing can generate a set of disjointed microplots of said diffusing enamel, microplots containing the microcrystals, the enamel paste preferably comprises a percentage of inorganic solid including the crystallizable glass frit which is at most 50% by weight of enamel paste, and even at most 30%, 20%, 15%, 10% or 5% and in particular at least 0.5%, 1% or 5%.

[0185] The term "crystallizable glass frit" preferably means that at least 30% by weight of the oxides contained in the glass frit react upon firing to form crystals. Suitable oxide frits include borosilicate frits, for example, bismuth borosilicate frits and zinc borosilicate frits. More details on glass frits are in patents US5153150 US6207285 or EP1888333.

[0186] The enamel paste may optionally contain up to about 20% (e.g., 0.1-20% or 2-10%) of growth seeds such as bismuth silicates, zinc silicates, and bismuth titanates. The seeds may include, but are not limited to, one or more of Zn2SiO4, Bi2SiO20, Bi4(SiO4)3, Bi2SiO5, 2ZnO.3TiO2, Bi2O3.SiO2, Bi2O3.2TiO2, 2Bi2O3.3TiO2, Bi7Ti4NbO21, Bi4Ti3O12, Bi2Ti2O7, Bi12TiO20, Bi4Ti3O12, and Bi2Ti4O11. Examples are in patents US6624104 and US 5208191 or EP1888333.

[0187] The organic medium may include or even consist of one or more of the following organic compounds: alcohols, esters, glycols, in particular glycol esters, terpineol. Terpineols, or terpinols or terpinoles, are unsaturated monocyclic monoterpene alcohols (monoterpenols) with the chemical formula CIQHI8O; The medium may comprise or even consist of one or more of the following organic compounds: diethylene glycol ethyl ether, diethylene glycol butyl ether, vegetable oils, mineral oils, low molecular weight petroleum fractions, tridecyl alcohol, synthetic or natural resins (e.g., cellulose resins or acrylate resins), propylene glycol monomethyl ether (PM), dipropylene glycol monomethyl ether (DPM), tripropylene glycol monomethyl ether (TPM), propylene glycol mono-n-butyl ether (PnB),dipropylene glycol mono-n-butyl ether (DPnB), tripropylene glycol mono-n-butyl ether (TPnB), propylene glycol mono-n-propyl ether (PnP), dipropylene glycol mono-n-propyl ether (DPnP), tripropylene glycol n-butyl ether (TPnB), propylene glycol monomethyl ether acetate (PMA), Dowanol DB (diethylene glycol monobutyl ether) marketed by Dow Chemical Company, USA, or other ethylene glycol or propylene glycol ethers.,

[0188] Drying eliminates the vast majority of the solvent (at least 80% for example) while limiting the risk of pollution of the surface by dust which would impact the transparency of the diffusing layer.

[0189] The process may include an operation of bending the first sheet of glass, said firing occurring during bending and possibly followed by tempering.

[0190] In particular, the baking oven can be in an industrial bending (quenching) line. Quenching does not modify the optical characteristics of the diffusing layer. The bending is done by gravitational collapse, for example as described in patents WO2007138214, W02006072721, or by suction, for example as described in patent W002 / 064519.

[0191] Glass frit is preferably in the form of particles with a D90 of at most 20 pm, especially 5 pm or even 4 pm. The particle diameter distribution can be determined using a laser granulometer.

[0192] In the case of screen printing, a textile or metal mesh screen, coating tools and a squeegee are preferably used, with thickness control being ensured by the choice of the screen mesh and its tension, by the choice of the distance between the first sheet of glass and the screen, by the pressures and speeds of movement of the squeegee.

[0193] The screen printing screen can be more or less fine for example 90T, 120T, 150T and 180T T corresponds to the number of threads per cm.

[0194] The parameter that can influence the dimension of the microplots and even the formation “threshold” for a layer of disjointed microplots (for a paste of given composition) is the thickness of the liquid film.

[0195] The thickness E0 of the liquid film depends on process parameters such as deposited speed, pressure of the screen printing squeegee, etc.

[0196] In particular the amount of inorganic solid per unit of printed surface will influence the result.

[0197] The glass-crystal diffusing layer is non-adhesive or "anti-stick". The glass sheet with the baked enamel layer can therefore be curved. The glass sheet with the enamel paste layer can be cooked during the curving. The present invention will be better understood and other details and advantageous characteristics of the invention will appear on reading the examples of automotive luminous glazed devices according to the invention illustrated by the following figures:

[0198] Figures 1 to 3 are schematic views of illuminable enamelled glazing 1 according to the invention.

[0199] Figures 4 to 7 are SEM scanning electron microscopy photographs of the surfaces of the enamelled glazing according to the invention in examples 1 to 4.

[0200] Figures 8 to 13 are SEM photographs in cross-sectional view of the enamelled glazing according to the invention in examples Nos. 1, 2 and 4.

[0201] Figures 14, 16, 18, 20 are SEM photographs of the surface of the enamelled glazing according to the invention in examples Nos. 1, 2, 3 and 4.

[0202] Figures 15, 17, 19, 21 are the previous photographs after image processing. Figure 22 is an SEM photograph of the surface of the enamelled glazing of example 6.

[0203] Figure 23 is a graph representing the ratio between the light transmission of the enamelled glazing according to the invention (with 6 points for examples 1 to 6 above) on the light transmission of the glazing without enamel as a function of the inorganic ratio R% in the enamel paste.

[0204] Figure 24 is a graph representing the haze (%) of the enamelled glazing according to the invention (with 6 points for examples 1 to 6 above) as a function of the inorganic ratio R% in the enamel paste

[0205] Figure 25 represents a schematic sectional and partial view of a luminous laminated glazing unit for a motor vehicle comprising an enameled glazing unit illuminated by the edge in one embodiment of the invention.

[0206] Figure 26 represents a schematic sectional view of a luminous automobile roof using luminous enamelled glazing according to the invention like that of Figure 1.

[0207] Figure 27 represents a schematic sectional view of a laminated luminous glazing (for example) comprising an enameled glazing illuminated by an internal edge which is the wall of a closed through hole in one embodiment of the invention.

[0208] Figure 28 represents a schematic front view of the illuminated enamelled glazing of Figure 27.

[0209] Figure 29 represents a schematic sectional and partial view of a luminous laminated glazing unit for a motor vehicle comprising an enameled glazing unit illuminated via a light source in one embodiment of the invention, the light source facing the face F4 and a light redirection element on the face F3. Figure 30 represents a schematic sectional and partial view of a luminous laminated glazing unit for a motor vehicle comprising an enameled glazing unit illuminated from the edge in one embodiment of the invention, the enameled glazing unit being between two sheets of glass.

[0210] Other details and advantageous characteristics of the invention will appear on reading the examples according to the invention illustrated by the following figures.

[0211] Please note that for the sake of clarity, the various elements of the objects represented are not necessarily reproduced to scale.

[0212] Figures 1 to 3 are schematic views of the illuminable enamelled glazings 1 according to the invention, each comprising on a first main face 11 a layer of enamel 2 with a plurality of transparent and translucent diffusing patterns 20 allowing the clearest possible vision through them and the most discreet, invisible patterns possible. The patterns are chosen to order:

[0213] - figure 1: set of nine diffusing rectangles (transparent and translucent) 2 of variable width increasing for example from 2 mm to 50 mm in particular moving away from a light injection zone for example the edge 10 of the glass being coupled to LEDs,

[0214] -figure 2: set of seven diffusing circles (transparent and translucent) for example centimetric

[0215] -figure 3: two diffusing circles (for example 10 cm by 10 cm)

[0216] Each Figure 1 to 3 presents a zoomed view at the microscopic scale (seen by SEM) on one of the scattering patterns showing a set of disjointed enamel micro-dots randomly distributed with large dots 20 and smaller dots 21.

[0217] The first sheet of glass is preferably extra-clear glass, for example OPTIWHITE 1.95mm. It can be curved, for example, and can be used as a side panel for vehicles, especially road vehicles, or for commercial counters, etc.

[0218] The main face 11 or the opposite face may include a peripheral masking layer of black enamel. The main face 11 may be covered by a functional film, for example a tinted film bonded to the first main face. To extract more light, a low-index layer, for example a porous silica layer, may be added to the first face under the tinted film, thus forming an optical isolator.

[0219] I. Examples of simple enamelled glazings Six examples No. 1 to 6 of enamelled glazings with a discontinuous diffusing layer are produced, comprising a first rectangular diffusing pattern measuring 3cm by 1cm, produced by screen printing using a crystallizable enamel paste comprising an organic medium, a glass frit and growth seeds on an Optiwhite extra-clear glass measuring 1.95mm. The product DV778640 is used, including bismuth silicate-based glass frit and growth seeds (to grow crystals on themselves), sold by PMI, with an organic medium 808018 by Ferro based on carbohydrate / cellulose (derived).

[0220] A 90T screen is used.

[0221] For the various examples, we simply varied the ratio R of inorganic solid by diluting more or less with the organic medium.

[0222] The enamel paste is fired above the glass transition temperature for 250s. A preliminary step of evaporation of the solvent can be carried out, for example, between 100°C and 200°C.

[0223] The enamel is vitrocrystalline comprising a vitreous binder with microcrystals generated by firing, and growth germs. The enamel is here translucent (semi-transparent). In examples 1 to 5, the diffusing layer forms a set of disjointed enamel micro-spots distributed randomly with large spots and smaller spots depending on the ratio R% of inorganic solid in the enamel paste.

[0224] Example 6 corresponds to a very diffusing enamel area with holes.

[0225] The following table 1 records for each example the ratio RO of organic medium, the ratio R% of inorganic solid, the wet thickness (continuous film) deposited, the wet thickness E0 or E1 after baking (E1 estimated by SEM section views for examples 1 to 5), the haze H, the light transmission TL, the sharpness C.

[0226] [Table 1]

[0227] Image blur and sharpness are preferably measured by a Hazemeter (such as BYK-Gardner Haze-Gard Plus) preferably according to ASTDM D1003 (without compensation). The haze of a continuous layer of this 15pm thick glass-crystal enamel is 100°.

[0228] Gloss was measured in gloss units (UB) using a Glossmeter, using the MICRO TRIGLOSS device (BYK-GARDNER) according to ISO 2813 (measurement on the diffusing layer side at an angle of 60°). Gloss ranges from 3 (example 1 or 6) to 140 (example 5). The gloss of bare glass is 159.

[0229] Clarity was measured. Clarity ranges from 3 (example 1 or 6) to 140 (example 5). The clarity of continuous enamel is 159.

[0230] The optical density was measured, which ranges from 0.15 (example 1) to 0.05 (example 5). The optical density of bare glass is 0.03.

[0231] This glass-crystal diffusing layer is non-stick. The glass sheet with the baked enamel layer can therefore be curved. The glass sheet with the enamel paste layer can be baked during bending.

[0232] Figures 4 to 7 are SEM photographs (magnification of 2500) of the surface of enameled glazing according to the invention respectively for the four examples Nos. 1 to 4, each showing a set of disjointed enamel microplots distributed randomly with large plots 20 and smaller plots 21 depending on the % ratio of inorganic solid in the enamel paste respectively. The microcrystals 22 are visualized in the large plots 20. Figures 8 to 13 are SEM photographs in cross-sectional view of the enameled glazing according to the invention in examples Nos. 1, 2 to 4, including thickness measurements (maximum height) of the large plots 20.

[0233] Figures 14, 16, 18, 20 are SEM photographs (magnification of 250) of the surface of the enamelled glazing according to the invention in examples Nos. 1, 2, 3 and 4.

[0234] Figures 15, 17, 19, 21 are previous photographs after image processing in order to define the geometric parameters of the microplot sets.

[0235] The parameters Am, Bm, Tm, Cm, Pm can be determined from the processing and analysis of these four black and white SEM images of the surface under a scanning electron microscope at a magnification of 250 times.

[0236] For SEM images, CBS mode is chosen, which gives images in chemical contrast. For each SEM image, an image threshold is performed from 90 to 255.

[0237] For example, the software called Image J is used for image processing and analysis. The surface S1 is chosen, for example 500pm by 340pm within the first diffusing pattern.

[0238] All particle sizes are taken into account by default as well as all circularities.

[0239] We count the number N of isolated plots and we measure the parameters Am, Bm, Tm, Pm and Cm (between 0 and 1).

[0240] The parameters are listed in the following Table 2.

[0241] [Table 2]

[0242] By choosing another analysis surface, for example 300pm by 300pm, we find similar results.

[0243] Figure 22 is an SEM photograph (magnification of 1000) of the surface of the enameled glazing in Example No. 6. The first diffusing pattern comprises a continuous enamel zone 2' with microcrystals 22 and having disjointed (micrometric) openings. The openings are of irregular shape, size and irregularly distributed. Some enamel "particles" 20' may be in the openings.

[0244] We use the previous image processing method (with the same analysis surface) to determine:

[0245] -the equivalent average diameter A'm (with openings having a base reduced to a circle) of said openings which is here 3pm

[0246] -an average distance Bm between the said neighboring openings which is here 4pm

[0247] -the coverage rate T'm of said openings which is here 15%.

[0248] Figure 23 is a graph representing the ratio between the light transmission TL1 of the enamelled glazing according to the invention (with six points for examples 1 to 6 above) on the light transmission of the TLO glazing without enamel as a function of the inorganic ratio R% in the enamel paste.

[0249] This ratio naturally increases with R and ranges from approximately 63.1 to 100%.

[0250] Figure 24 is a graph representing the haze (%) of the enamelled glazing according to the invention (with six points for examples 1 to 6 above) as a function of the inorganic ratio R% in the enamel paste.

[0251] This blur naturally decreases with R and ranges from approximately 63.1 to 100%.

[0252] IL Examples of luminous laminated glazing

[0253] Figure 25 represents a schematic sectional and partial view of a luminous laminated glazing unit for a motor vehicle comprising an enameled glazing unit illuminated by the edge in one embodiment of the invention.

[0254] This is a 100 laminated glazing which is a roof with a 10 edge and main external faces called face F1 and face F4 which comprises:

[0255] - a first sheet of glass 1, forming internal glazing, passenger compartment side for example rectangular (of dimensions 300X300 mm for example), made of mineral glass, having a main face 11 corresponding to the face F3 and another main face 12 which is the face F4, and a preferably rounded edge 10 (to avoid flaking) here longitudinal edge (or in a lateral variant), for example a sheet of sodium-calcium silicate glass, extra-clear such as Diamant glass marketed by the company Saint-Gobain Glass, of thickness equal for example to 2.1 mm, glass with a refractive index n1 of the order of 1.51 at 550 nm or Optiwhite glass of 1.95 mm, possibly with an ITO 15 stack on the F4 face (passenger compartment face) - a lamination interlayer 3, for example a clear or tinted PVB with a thickness of 0.76 mm, preferably with a haze of at most 1 ,5%, with a 30 slice here longitudinal offset from the longitudinal 10 slice towards the center of the glass,lamination interlayer of refractive index n, f less than n1, equal to 1.48 at 550nm

[0256] - a second sheet of glass 1', of the same dimensions as the glass 1, forming external glazing, with a composition for a tinted solar control function (VENUS VG10 or TSA 4+ glass marketed by the company Saint-Gobain Glass) for example of thickness equal to for example 2.1 mm) and / or clear glass covered with a solar control coating, or a tinted plastic film, with a main face called internal or lamination 12' or F2 opposite the face 12 or F3, and another main face 11' corresponding to the face F1, and a slice 10' here longitudinal.

[0257] The lamination interlayer may comprise a transparent polymeric sheet, for example PET, in particular covering the surface, for example at least 90%. This sheet may be coated with a transparent electrically conductive coating, for example for solar control and / or component power supply. For example, this is the PVB / sheet / PVB assembly and in particular PVB / PET / PVB.

[0258] The first glass sheet 1 here comprises a peripheral recess or through hole along the longitudinal edge 10, preferably of a dimension smaller than the longitudinal edge.

[0259] Light-emitting diodes 4 extend along the edge of the first glass sheet 1. These are side-emitting diodes housed in the recess. Thus, these diodes 4 are aligned on a PCB support 5, for example a parallelepiped strip, preferably as opaque as possible (not transparent) and their emitting faces are parallel to the PCB support and opposite the edge 10 in the recessed edge portion. The PCB support is fixed, for example, by glue 7 (or double-sided adhesive) on the edge of the face F2 12', and here is engaged in a groove between the faces F2 and F3 made possible by the sufficient removal of the edge 30 of the PVB. A peripheral masking strip 6 made of opaque enamel is added to the face F2 which can mask the PCB support and even the outgoing light in this area.

[0260] The distance between the diodes and the wafer 10 is reduced as much as possible, for example from 1 to 2 mm. The space between each chip and the optically coupled wafer 10 can be protected from any pollution: water, chemical etc., this in the long term as during the manufacture of the luminous glazing 100.

[0261] The luminous glazing has a polymeric encapsulation 8 for example in black polyurethane, notably PU-RIM (reaction in mold in English). It is double-sided at the edge of the glazing. This encapsulation ensures long-term sealing (water, cleaning product, etc.). The encapsulation also provides a good aesthetic finish and allows the integration of other elements or functions (reinforcing inserts, etc.).

[0262] As described in WO2011092419 or WO2013017790, the polymeric encapsulation may have a through-recess closed by a removable cover for placing or replacing the diodes.

[0263] The luminous glazing 100 may have a plurality of light zones, the light zone(s) preferably occupying less than 50% of the surface of at least one face, in particular of given geometry (rectangular, square, round, etc.)

[0264] The light ray (after refraction on the edge 10) propagates by total internal reflection (at the level of the face F3 and the face F4) in the first glazing 1 forming a light guide.

[0265] For light extraction, the diffusing layer 2 in non-stick enamel according to the invention is deposited on the face F3 12 (or F4 11 as a variant). It comprises a vitrocrystalline matrix 20 incorporating microcrystals and is in the form of separate pads. Several series of diodes can be provided (one edge, two edges, three edges, over the entire periphery, controlled independently and even of different colors. Diodes emitting white or colored light can be chosen for ambient lighting, reading lighting, etc. Red light can be chosen for signaling, possibly alternating with green light.

[0266] The firing of the diffusing layer 2 can be carried out before or during the bending.

[0267] The roof 100 can form, for example, a fixed luminous panoramic roof 1000 of a motor vehicle such as a car, mounted from the outside on the bodywork 8' via an adhesive 61' as shown in figure 26.

[0268] This laminated luminous glazing 100 can alternately form a front or rear quarter light (possibly by removing the encapsulation). The diffusing layer forms, for example, a turn signal repeater or a LOGO. It is then on the first clear or extra-clear glazing, here the outermost, on face F1 or preferably on face F2 on the lamination face side. Optionally, an opaque masking layer is on the internal glazing - tinted or not - for example on face F3.

[0269] This laminated luminous glazing can alternatively form a front windshield (possibly by removing or adapting the encapsulation). The diffusing layer forms, for example, an anti-collision signal for the driver and is on the first innermost clear or extra-clear glazing on face F4 or on face F3 in particular, forming a band along the lower longitudinal edge. For example, the light comes on (red) when a vehicle in front is too close. The second glazing is also a clear or extra-clear glass. Alternatively, the first glass sheet is set back from the outer glass sheet 1.

[0270] Figure 27 represents a schematic sectional view of a laminated luminous glazing 200 (for example) comprising an enameled glazing illuminated by an internal edge which is the wall of a closed through hole in one embodiment of the invention.

[0271] As in figure 26, the laminated glazing 200a comprises a first sheet 1, bonded via a lamination interlayer 3 to a second sheet of glass 1'.

[0272] A through hole 9 has been drilled through the first sheet 1, creating in the latter an internal edge 17 for housing LEDs 4 with their emitting face facing the internal edge 17 (front-emitting diodes). A solar control or heating layer 16 is on the face F2 12'. The through hole is obstructed for example by a metal pad.

[0273] Alternatively, it is a monolithic glazing (window, side, etc.) possibly without a through hole

[0274] Alternatively, an optical module such as a guide element is placed between the diodes 4 and the wall 17, for example as described in patent WO2018178591.

[0275] Figure 28 represents a schematic front view of the illuminated enamelled glazing of figure 27. The diffusing pattern is for example a star 2 formed from a set of studs 20 and small studs 21 of non-stick and translucent enamel.

[0276] Figure 29 represents a schematic sectional and partial view of a luminous laminated glazing of a motor vehicle 300 comprising an enameled glazing illuminated via a light source 4 in one embodiment of the invention, light source 4 facing the face F4 11 and a light redirection element 19 such as a prismatic film, in particular a reflector on the face F3 12 or a prismatic film on the face side F4 11, the hole in the sheet 1 is thus omitted. The light source 4 is still a set of LEDs. The layers 15 and / or 16 of the previous glazings can be retained.

[0277] Figure 30 represents a schematic sectional and partial view of a luminous laminated glazing unit for a motor vehicle 400 comprising an enameled glazing unit illuminated by the edge in one embodiment of the invention, the enameled glazing unit being between two sheets of glass (the tinted outer sheet 1 and a sheet of glass 18 with main faces 182 on the interlayer side and 181 opposite) and more precisely between two layers of lamination interlayer 31, 32 (PVB, EVA etc). The light source 4 is again a set of LEDs facing the edge of the sheet 1. The layer 15 is kept on the innermost face 181. For example, the diffusing layer is on both faces of the sheet 1 (two offset patterns).

[0278] Of course, the laminated glazing of figure 25 or 27 or 29 or 30, in particular a road vehicle roof (automobile), may include other elements such as:

[0279] - one or more functional layers (on a PET film etc.) within the laminate

[0280] - one or more sensors

[0281] - within the laminated glazing between the faces F1 and F4 and even between F2 and F3, an electrically controllable device with variable diffusion and / or tint, in particular liquid crystal or electrochromic, or a multi-pixel screen or an additional luminous element, offset or opposite the diffusing layer

[0282] - a low index optical isolating element with a refractive index lower than the refractive index of the first glass sheet, between the first face and the F2 face, tinted in particular between the first face and the tinted lamination interlayer, in particular a porous silica layer on the first face or a fluorinated film in particular ETFE or FEP.

[0283] The diffusing layer can be of any shape and can even include diffusing particles as a partial or total replacement for the microcrystals, it can include luminescent particles and a dedicated light source, in particular LIV, is coupled to the first glass sheet.

Claims

DEMANDS 1. Enamelled substrate (1, 100 to 400) comprising a first sheet of glass (1) having on a first main face (11, 12) a diffusing layer (2), of diffusing enamel, comprising a vitreous matrix, the layer comprising at least a first diffusing motif of at least 0.1 mm and of given surface S0, characterized in that the vitreous matrix is ​​vitreocrystalline thus comprising microcrystals in a vitreous binder, the microcrystals being diffusing and in that the first diffusing motif is discontinuous, the diffusing layer comprises a weight content of colouring additives of at most 10%, of the total weight of the enamel.

2. Enamelled substrate according to the preceding claim characterized in that the first sheet of glass with the diffusing layer has: - a light transmission factor of at least 70%, and even at least 80%, - a blur of at most 80% and even at most 55%.

3. Enamelled substrate according to any one of the preceding claims characterized in that the diffusing layer comprises a weight content of colouring additives in particular black pigments of at most 5% or 1% of the total weight of the enamel and even down to 0%.

4. Enamelled substrate according to any one of the preceding claims characterized in that the first diffusing pattern comprises a set of disjoint microplots of said diffusing enamel and in that by defining within the first diffusing pattern an analysis area S1 less than SO, S1 being at least 50pm by 50pm and at most 100pm by 600pm, and an area S2 which is the sum of the areas of the microplots in this area S1 the first diffusing pattern is defined by an equivalent average diameter Am of the microplots less than 10pm and at least 1pm, the average distance Bm is less than 5pm and preferably at least 1pm and preferably at least in said analysis area, the first diffusing pattern has a coverage rate Tm of said microplots which is the area S2 divided by the area S1, Tm is less than 50%.

5. Enamelled substrate according to any one of claims 1 to 3 characterized in that the first diffusing motif comprises an enamel zone including disjointed through holes, and in that by defining within the first diffusing motif an analysis surface S'1 smaller than S0, S'1 being at least 50 pm by 50 pm and at most 100 pm by 600 pm, and a surface S'2 which is the sum of the areas of the openings in this surface S'1, the first diffusing motif is defined by an equivalent average diameter A'm of the openings less than 20 pm, an average distance B'm between said neighboring openings is less than 20 pm, and preferably at least within said analysis surface, the first diffusing pattern has a coverage rate T'm of said openings which is the area S'2 divided by the area S'1, T'm is less than 50%.

6. Enamelled substrate according to any one of the preceding claims characterized in that it further comprises a light source, in particular a plurality of inorganic light-emitting diodes, which is optically coupled to the first glass sheet forming a light guide, in particular injection of light from the light source through a slice of the first glass sheet or a wall of a hole in the first glass sheet or through the first main face or a second main face opposite the first main face, in particular direct optical coupling or via optics in particular a light redirection element on the first or second main face and offset from the diffusing layer.

7. Enamelled substrate according to any one of the preceding claims characterized in that the vitreous matrix comprising a vitreous binder, the vitreous binder and / or the microcrystals of the vitreocrystalline matrix is ​​based on bismuth and / or zinc silicate or bismuth and / or zinc borosilicate.

8. Laminated glazing comprising the enamelled substrate according to any one of claims 1 to 7, characterized in that it comprises: - said first sheet, preferably made of clear or extra-clear glass - a lamination interlayer (3), preferably made of PVB, possibly tinted - and a second transparent sheet (1') of glass or plastic, preferably tinted, preferably the first main face is on the interlayer side of the lamination, the diffusing layer being in adhesive contact with the interlayer of the lamination or covered by a functional element (in particular a functional element in contact with the diffusing layer and in particular in the interplot area between the microplots in contact with the first bare face or with an underlayer as already described) preferably in adhesive contact with the interlayer of the lamination.

9. Laminated glazing according to the preceding claim characterized in that the first sheet is the inner glazing and preferably the first main face (12) is the inner face called face F3 or the first sheet is between the second transparent sheet and a third sheet of glass (forming an internal light guide, within the lamination interlayer).

10. Laminated glazing according to any one of claims 8 to 9 characterized in that it comprises a functional element, in particular transparent, selected from one or more of the following elements: - a layer of silica, particularly porous and for example ground-based, forming an anti-reflective layer - a masking layer possibly adjacent to the diffusing layer, particularly a peripheral layer, in particular an enamel layer - an electrically conductive layer, in particular an electrode, a power supply layer for (opto)electronic components or a heating layer, in particular a transparent conductive oxide layer, particularly within laminated glazing - a solar control (and / or low-emissivity) layer, in particular a coating on the F4 face comprising a conductive transparent oxide functional layer or a metallic functional layer within the laminated glazing - within the laminated glazing, an electrically controlled device with variable diffusion and / or tint, in particular with liquid crystals or electrochromic, or a multi-pixel screen or an additional luminous element, offset or opposite the diffusing layer. - a low index optical insulating element with a refractive index lower than the refractive index of the first sheet of glass, between the first face and the second sheet of tinted glass, in particular between the first face and the tinted laminate interlayer, in particular a layer of porous silica on the first face or a fluorinated polymer film.

11. Enamelled substrate or laminated glazing according to any one of the preceding claims characterized in that it forms glazing for land, water or air vehicles, or as building glazing, in particular: - a laminated, domed roof, the first sheet of glass is the inner glazing or sandwiched between a second sheet of glass and a transparent sheet of glass or polymer - a rear window, specifically the first pane of glass is the outer glazing, the diffusing layer is on the passenger compartment side - a lateral, laminated or monolithic, the first sheet of glass is the inner or outer glazing - a laminated, curved windscreen, the first sheet of glass is the inner or outer glazing.

12. A process for manufacturing an enamelled substrate comprising the formation of a diffusing layer of diffusing enamel on a first principal face of a first sheet of glass involving, in this order: - a deposit on the first sheet of glass of a film of a vitrifiable liquid composition called enamel paste comprising a mixture of an organic medium and a glass frit, with a given glass transition temperature Tg1, - firing at a temperature Te above the glass transition temperature Tg1 of the glass frit, characterized in that the glass frit is crystallizable and the enamel paste preferably contains growth nuclei, preferably at most 20% of nuclei growth, cooking generates the formation of a vitrecrystalline matrix containing diffusing microcrystals and in that the diffusing layer is discontinuous.

13. A method for manufacturing an enamelled substrate according to the preceding claim of a method characterized in that the firing generates a set of disjoint microplots of said diffusing enamel, microplots containing the microcrystals, the enamel paste preferably comprising a percentage of inorganic solid including crystallizable glass frit which is at most 30% by weight of enamel paste.

14. A method for manufacturing an enameled substrate according to any one of the preceding claims, characterized in that the deposition is by screen printing.

15. A method for manufacturing an enameled substrate according to any one of the preceding claims, characterized in that the method comprises a bending operation of the first sheet of glass, said firing occurring during the bending and optionally followed by quenching.

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