Glazing substrate

Abstract

The present invention relates to a glazing substrate (1), a first face (11) of which has a mean surface (110) normal to a main normal direction and is textured such that it has at least: - first surface segments (111) with an orientation normal to a first normal direction, which forms an angle of more than 10° with the main normal direction, - second surface segments (112) with an orientation normal to a second normal direction, which forms an angle of more than 10° with the main normal direction, and an angle of more than 20° with the first normal direction, the first face (11) being at least partially covered by a coating comprising at least a first functional layer (3). According to the invention, the thickness of the functional layer (32) on the second surface segments (112) is greater than twice the thickness of the functional layer (31) on the first surface segments (111).

Description

DESCRIPTION TITLE: Glazing substrate Field of the invention [1] The present invention relates to glazing. In particular, the invention relates to glazing comprising at least one coated glazing substrate intended for controlling the passage of at least some solar radiation through the glazing. Prior art [2] Glazed surfaces often form the walls of buildings or vehicles. They are most often formed by glazing comprising one or more stacked glazing substrates. In general, it is desirable for these glazings to transmit solar radiation. In certain cases, however, it is also desirable for this glazing to block the transmission of certain solar radiation, in particular non-visible rays such as infrared or ultraviolet rays, or certain visible light rays. [3] This control of solar radiation transmission can in particular be achieved by coatings deposited on a glazing surface, in order to filter the radiation transmitted through this glazing. [4] In this way, glazing can be optimized in particular to contribute more effectively to the thermal control of the buildings and vehicles of which it forms part of the walls. Thus, by way of example, a glazing with a coating that filters infrared radiation, by absorbing or reflecting it, has the effect of protecting the building or vehicle of which it forms part of the wall from excessive temperature increases associated with exposure to the sun. Conversely, a glazing that transmits infrared radiation well advantageously allows the building or vehicle of which it forms part of the wall to be heated by solar exposure. [5] However, the radiation transmission characteristics of existing glazing are fixed at the time of manufacture, and cannot easily be adapted based on circumstances. However, such an adaptation would be useful. For example, a building or a vehicle can advantageously be heated by solar radiation at certain times, for example in winter or at certain times of the day when the temperature is relatively low. Conversely, the same building or vehicle must be protected from solar radiation at other times, for example in summer or at certain times of the day when temperatures are high, to avoid excessive temperature increases. In practice, such control of radiation transmission through glazings is often achieved with blinds, which are often cumbersome to operate and obstruct visibility through the glazing. Disclosure of the invention [6] The present invention aims in particular to overcome these drawbacks of the prior art. [7] In particular, the invention aims to provide a glazing comprising a glazing substrate having at least one coating, the coating allowing a greater or lesser transmission of radiation through the glazing, depending on the circumstances.These goals, and others which will become clearer hereinafter, are achieved by means of a coated glazing substrate, suitable for being incorporated into a glazing, this substrate having at least a first face, this first face having a mean surface normal to a main normal direction, and being textured so as to have at least first surface segments with an orientation normal to a first normal direction, which forms an angle of more than 10° with the main normal direction, and second surface segments with an orientation normal to a second normal direction, which forms an angle of more than 10° with the main normal direction, and an angle of more than 20° with the first normal direction, this first face being at least partially covered with a coating comprising at least one first functional layer. According to the invention, the thickness of this functional layer on the second surface segments is greater than twice the thickness of this functional layer on the first surface segments. [8] The thickness of the functional coating layer thus varies based on the orientation of the textured surface segments. This different thickness enables the effect of this functional coating layer, particularly on the transmission of light radiation, is different depending on the orientation of this light radiation. [9] For the purposes of the following description of the invention, a surface segment will be considered to belong to the group of "first surface segments", or respectively to the group of "second surface segments", when its normal orientation forms an angle of less than 5° with the first normal direction, or respectively with the second normal direction. 

[10] Preferably, the first normal direction forms an angle of more than 20°, or even more than 30°, and even more preferably more than 40° with the main normal direction. 

[11] Preferably, the second normal direction forms an angle of more than 20°, or even more than 30°, and even more preferably more than 40° with the main normal direction. 

[12] Preferably, the second normal direction forms an angle of more than 40°, or even more than 60°, and even more preferably more than 80° with the first main normal direction. 

[13] Preferably, the functional layer, or at least one of the functional layers, has light absorption and / or light reflection characteristics. 

[14] Preferably, the effectiveness of these absorption and / or reflection characteristics increases with the thickness of the functional layer. 

[15] According to an advantageous embodiment, the first face has at least third surface segments, oriented in directions distinct from the orientation directions of the first surface segments and the second surface segments, these first, second and third surface segments being covered by the functional coating layer, the thickness of which is variable depending on the orientation of each of the surface segments. 

[16] Advantageously, the coating comprises at least one second functional layer, the thickness of which is variable based on the orientation of each of the surface segments. 

[17] The thickness of this second functional layer can be varied, depending on the orientation of each of the surface segments, according to the same rule as the thickness of the first functional layer, or according to a different rule. 

[18] Preferably, the first face is textured so as to have protrusions whose “peak-to-valley” height is between 0.5 and 150 μm, more preferably from 1 to 120 μm. 

[19] According to an advantageous embodiment, the first face is textured so as to have protrusions forming repeated or even periodic patterns, each pattern comprising at least one of the first surface segments and at least one of the second surface segments. 

[20] Such texturing can conventionally be achieved by laminating a glazing substrate. 

[21] According to another advantageous embodiment, the first face is textured so as to have a random shape, comprising first and second surface segments. 

[22] Such texturing can conventionally be achieved by chemical etching of one face of a glazing substrate, for example with an acid, or by mechanical action such as sandblasting. 

[23] Advantageously, the first functional layer is three times, or even six times, or preferably ten times thicker on the second surface segments than on the first surface segments. 

[24] According to a particular embodiment of the invention, the first functional layer may even be completely absent from the first surface segments, while being present on the second surface segments. 

[25] According to an advantageous embodiment, the thickness of the functional layer is maximum on one of the surface segments, normal to a so-called "dominant" direction, and the thickness of the functional layer on each of the other surface segments decreases as the angle between the dominant direction and the normal direction to this surface segment increases. 

[26] Advantageously, said functional layer is selected from metal layers based on a metal or a metal alloy, metal nitride layers and metal oxynitride layers. 

[27] The present invention also relates to a glazing comprising a glazing substrate as described hereinbefore. 

[28] According to a particularly advantageous embodiment, the present invention relates in particular to a glazing comprising a glazing substrate as described above and a transparent layer with an optical index substantially identical to the optical index of this glazing substrate, pressed against the first face of this glazing substrate. 

[29] In such glazing, the transparent layer having an optical index substantially identical to the optical index of this glazing substrate can suppress the blurring or distortion of light beams that is normally induced by the textured surface. The glazing can thus be used as a non-textured transparent glazing. However, it retains the specific feature of the glazing substrate according to the invention, in which the functional coating layer has an effect, particularly on the transmission of light radiation, which is different depending on the orientation of this light radiation. 

[30] The present invention also relates to a method for manufacturing a glazing substrate, which comprises a step of applying at least one functional coating layer to a first face of a glazing substrate, this first face having a mean surface normal to a main normal direction, this first face having a textured surface with surface segments the orientation of which is varied, this step of applying at least one functional coating layer comprising projecting this coating onto the first face by a directional deposition method, in which the material constituting the functional coating layer is projected onto this face along a determined direction, the determined direction forming an angle greater than 20° with the main normal direction of the first face, an angle greater than 40° with some of the surface segments, and an angle of less than 20° with some others of the surface segments. 

[31] Preferably, this determined direction forms an angle of more than 30°, or even more than 40°, and even more preferably more than 45° with the main normal direction of the first face. 

[32] Preferably, this determined direction forms an angle of more than 60°, or even more than 80°, and even more preferably more than 90° with some of the surface segments, and an angle of less than 10° with some other of the surface segments. 

[33] Advantageously, this directional deposition method is a magnetron sputtering method. 

[34] According to another possible definition, the present invention relates to a coated glazing substrate, suitable for being incorporated into a glazing, the substrate having at least a first face textured so as to have a plurality of surface segments having varied orientations, this first face being at least partially covered by a coating comprising at least a first functional layer, in which the thickness of the functional layer is at a maximum on one of the surface segments, normal to a so-called "dominant" direction, and in that the thickness of the functional layer on each of the other surface segments decreases as the angle between the dominant direction and the direction normal to the surface segment increases. Description of the figures 

[35] The invention will be better understood on reading the following depiction of preferred embodiments, given merely as a figurative and non-limiting example, and accompanied by the figures among which:- Figure 1 is a schematic representation of a portion of a textured glazing substrate, intended for being incorporated in a glazing according to one embodiment of the invention.- Figure 2 is a schematic representation of a device for depositing a coating on the glazing substrate shown in Figure 1.- Figure 3 is a schematic representation of the glazing substrate portion shown in Figure 1, on which a coating has been deposited using the method implemented by the device shown in Figure 2.- Figure 4 is a schematic representation of a glazing portion comprising the coated glazing substrate portion of Figure 3.- Figure 5 is a schematic representation of the transmission of solar radiation through a glazing according to one embodiment of the invention.- Figure 6 is a schematic cross-sectional view of a portion of a textured glazing substrate according to another embodiment.- Figure 7 is a schematic cross-sectional view of the textured glazing substrate shown in Figure 6, highlighting a first plurality of surface segments on the textured surface.- Figure 8 is a schematic cross-sectional view of the textured glazing substrate shown in Figure 6, highlighting a second plurality of surface segments on the textured surface. Description of embodiments 

[36] Figure 1 schematically shows a portion of a glazing substrate 1, intended to form part of a glazing according to one embodiment of the invention. 

[37] A glazing substrate within the meaning of the present description may consist of a sheet of glass or any other material used in glazings as a substitute for glass, in particular an organic polymer, in particular a polycarbonate. It generally offers good light transmission, above 50% and, more often, above 70% (measured according to ISO 9050:2023 with illuminant D65). 

[38] This glazing substrate 1 is in the form of a plate which, in the embodiment shown, is flat. In other embodiments, however, the glazing substrate may have a different shape. It can be curved, for example, to form a vehicle glazing. A person skilled in the art would have no difficulty in adapting the features of the flat glazing substrate described below to implement the invention on such curved glazing substrates. Curving can typically be carried out on a coated substrate using techniques that are well known to a person skilled in the art. 

[39] This glazing substrate 1 shown in Figure 1 has a first face 11 which, in the embodiment shown, is intended to face outwards from a building or vehicle, and a second face 12, opposite the first face 11, which is intended to face inwards. 

[40] The second face 12 has a smooth surface, extending in a plane normal to an axis 10. 

[41] The first face 11 of this glazing substrate 1 has a textured surface. A textured surface, within the meaning of the present description, is a surface made up of a plurality of surface segments of varying orientations, which form a plurality of recessed or protruding patterns, which may be periodic, aperiodic, or random, with respect to the mean surface of the textured surface. 

[42] The textured surface is thus characterized by a mean surface, which corresponds to the apparent surface at a macroscopic level, and by surface segments, which are visible at a microscopic level and which may present an inclination with respect to the mean surface. The mean surface of the first face 11 is generally parallel to the surface of the second face 12. 

[43] Two main categories of glazing substrates with textured surfaces are known: substrates with a surface roughened by the action of a chemical, e.g. an acid, or by mechanical action, e.g. sandblasting, and substrates with a textured surface printed by lamination or laser (Direct Laser Interface Patterning). 

[44] The characteristics of a textured surface can be defined, in particular for frosted surfaces, by a roughness parameter Ra, corresponding to the arithmetic mean of the absolute distance of each point on the surface, measured from the mean surface. Preferably, this roughness parameter Ra is at least 0.5 μm. In order to define the features of a textured surface, the roughness parameter RSm, which is the mean value of the widths of the patterns of the surface, may additionally be used. The RSm parameter can thus range, for example, from 10 μm to 100 μm. It is also possible to measure the thickness between the lowest trough of the pattern and its highest ridge or peak, which corresponds to the value or height known as "peak to valley". The roughnesses Ra and RSm are defined in a conventional manner according to standard ISO 4287:1997. Such frosted glazing substrates are commercially available, for example under the names SATINOVO® or SatenGlas®. 

[45] In some cases, glazing substrates with textured surfaces are obtained by rolling a molten glass sheet between rollers, at least one of these rollers having raised patterns which are reproduced in negative on the corresponding surface of the glass sheet. The range of textured glazing substrates marketed under the names DECORGLASS® or MATERGLASS® are thus known. 

[46] Glazings or glazing substrates with textured surfaces are well known to those skilled in the art. This texturing of a surface is commonly used so that radiation incident on this surface, with a given angle of incidence, is reflected and transmitted by this surface in a plurality of directions. This incident radiation is thus transmitted and reflected diffusely by the surface. 

[47] In the embodiment shown in Figure 1, the first face 11 of the glazing substrate 1 has a mean surface 110 (shown schematically in the figures by dotted lines) which is flat, normal to the axis 10, and therefore parallel to the smooth surface of the second face 12. In the rest of the description and in the figures, all axes normal to the mean surface 110 of the first face 11 will be considered as constituting the axis 10. 

[48] Because of the texture, the surface of this first face 11 is made up of a plurality of surface segments, at least some of which have different orientations from that of the mean surface 110. 

[49] In the embodiment shown, the first face 11 has a periodic regular textured surface, composed of strips forming first surface segments 111, having a first orientation different from that of the mean surface 110, alternating with strips forming second surface segments 112, having a second orientation different from that of the mean surface 110 and different from the first orientation of the first surface segments 111. 

[50] In the embodiment shown in Figure 1, the first surface segments 111 thus have a first orientation normal to an axis 101, which forms an angle α1 of between 40° and 50° with the axis 10. The second surface segments 112 have a second orientation normal to an axis 102, which forms an angle α2 of between 40° and 50° with the axis 10 and an angle of between 80° and 100° with the axis 101. 

[51] The protrusions of the textured surface, which are composed of alternating surface segments 111 and 112, are shown schematically in the figures with very large dimensions, with respect to the thickness of the glazing substrate 1. In practice, however, textured surface protrusions on glazing substrates generally have a "peak-to-valley" height of between 1 and 50 μm, which is much less than the thickness of the glazing substrates, which can be several millimeters. 

[52] In the example shown in Figure 1, the textured surface of the first face 11 is composed of two groups of surface segments 111 and 112, with the surface segments in each of these groups having identical or similar orientations. It is also possible, in other embodiments of the invention, for the textured surface of the glazing substrate to be textured in any other way. It may, for example, have a geometric appearance or a blurred, sandblasted, etc. appearance. In such cases, the textured surface can have surface segments with varied, regular or random orientations. 

[53] Figures 6 to 8 show schematically, in cross-section, an example of a portion of such a glazing substrate 6 which constitutes a flat plate. This glazing substrate 6 has a first face 61 of the glazing substrate 1, the surface of which is randomly textured. The first face 61 has a mean surface 610 (shown schematically in the figures by dotted lines) which is flat, normal to an axis 60. This glazing substrate 6 has a second face 62 opposite the first face 61, which is smooth, flat and normal to the axis 60. 

[54] Because of its texture, the surface of the first face 61 is made up of a plurality of surface segments with different orientations. Even if the orientation of each surface segment is random, it is possible to identify groups of surface segments with identical or similar orientations. 

[55] Thus, by way of example, Figure 7 shows the portion of the glazing substrate 6 on which first surface segments 611 have been highlighted, the normal direction of which is identical or similar to an axis 601 that forms an angle α3 of 30° with the axis 10. In the present description, the direction normal to a surface segment is considered to be identical or similar to an axis if it forms an angle of less than 5° with this axis. Thus, the directions normal to the first surface segments 611 shown in Figure 7 form angles of between 25° and 35° with the axis 60. 

[56] Similarly, Figure 8 shows the portion of the glazing substrate 6 on which second surface segments 612 have been highlighted, the normal direction of which is identical or similar to an axis 602 that forms an angle α4 of 30° with the axis 10 and that forms an angle of 60° with the axis 601. Thus, the directions normal to the second surface segments 612 shown in Figure 8 form angles of between 25° and 35° with the axis 60, and form angles of between 50° and 70° with the directions normal to the first surface segments 611. 

[57] To carry out the invention, the textured surface must have at least:- a first group of surface segments, having the same or similar orientation (e.g. forming an identical angle with the mean surface, to within plus or minus 5°) to that of a first axis which is inclined by at least 20° with respect to the mean surface, and- a second group of surface segments, having the same or similar orientation (e.g. forming an identical angle with the mean surface, to within plus or minus 5°) to that of a second axis which is inclined by at least 20° with respect to the mean surface, and at least 40° with respect to the orientation of the first axis. 

[58] In the embodiment shown in Figures 1 to 4, the first surface segments 111 belonging to the first group of surface segments may account for 40% to 60% of the textured surface of the glazing substrate 1. In other embodiments, the surface segments belonging to the first group of surface segments may represent a smaller proportion of the total surface area of the textured surface of the glazing substrate, for example 5% to 40%. 

[59] This proportion of the total surface area of the face of the glazing substrate occupied by the surface segments belonging to the first group of surface segments may be relatively low, when the textured surface has a random protrusion as shown in Figures 6 to 8, for example produced by acid etching on the surface. In such a case, each surface segment may have a random orientation, and surface segments meeting the criteria to belong to the first group of surface segments may represent only 3% to 20% of the textured surface. 

[60] According to the invention, the textured surface of the first face 11 or 61 carries a coating, which is deposited on this textured surface in such a way as not to be homogeneously distributed over the different surface segments of the textured surface. 

[61] Conventionally, such a coating can be formed by a set of thin layers successively deposited on the surface of the glazing substrate. Preferably, at least one of these thin layers, hereinafter referred to as the "functional layer", has an effect on the transmission of radiation through the glazing substrate. Thus, for example, this functional layer can have properties that absorb at least some of the solar radiation, or reflective properties for at least some of the solar radiation. 

[62] The functional layer is typically selected from metal layers based on a metal or metal alloy, metal nitride layers and metal oxynitride layers. The functional layer can be essentially in metallic form, in particular based on silver, palladium, niobium, tungsten, stainless steel, titanium, chromium, molybdenum, zirconium, nickel, tantalum, zinc, or alloys such as NiCr, NiCrW, WTa, WCr, NbZr, TaNiV, CrZr and NbCr. The functional layer can be a nitride or sub-nitride, i.e., a nitride with a sub-stoichiometric nitrogen content, in particular a nitride selected from TiN, NiCrWN, NiVN, TaN, CrN, ZrN, CrZrN, TiAIN, TiZrN, WN, SiZrN and SiNiCrN. Advantageously, the functional layer can be selected from layers based on Ag, Ti, TiN, Nb, NbN, Ni, NiN, Cr, CrN, NiCr, NiCrN. According to preferred embodiments, the functional layer is a TiN titanium nitride layer or a silver or NiCr nickel-chromium alloy metal layer. The functional layer is generally from 1 nm to 50 nm in thickness. 

[63] The coating can also comprise dielectric modules, formed by one or more dielectric layers above and below the functional layer. “Dielectric layer” within the meaning of the present invention should be understood as meaning that, from the perspective of its nature, the material is “nonmetallic”, that is, is not a metal. In the context of the invention, this term denotes a material exhibiting an n / k ratio over the entire wavelength range of the visible region (from 380 nm to 780 nm) which is equal to or greater than 5. Dielectric layers are typically selected from metal oxides, nitrides or oxynitrides, in particular oxides, nitrides or oxynitrides of one or more elements selected from titanium, silicon, aluminum, zirconium, tin and zinc. They typically have an additional thickness of 2 to 100 nm. 

[64] In a preferred embodiment, the functional coating layer can be deposited by a directional deposition method, in which the material constituting the coating is deposited in a determined direction. For example, in the preferred embodiment shown in the figures, this method can be a sputtering method, in particular magnetic field-assisted sputtering, known as magnetron sputtering, which is well known to those skilled in the art for depositing thin films on glazing. In such a method, a magnetron projects a beam of particles, the beam being centered on a predetermined direction. 

[65] According to a preferred embodiment, the deposition of the functional coating layer on the textured first face 11 of the glazing substrate 1 is carried out by such a directional deposition method oriented along an inclined direction, distinct from the direction of the axis 10 normal to the mean surface 110 of the first face 11. 

[66] Thus, preferably, this deposition of the functional coating layer can be carried out by sputtering, in particular by magnetron sputtering, in an inclined direction in order to project the particle beam forming the coating in an inclined direction, distinct from the direction of the axis 10 normal to the mean surface 110 of the first face 11. 

[67] Figure 2 schematically shows a device for implementing such a deposition of the functional coating layer 3. In this device, a magnetron 2 projects a beam of particles 21 onto the first textured face 11 of the glazing substrate 1. 

[68] The magnetron 2 is configured so as to project its particle beam 21 in a direction 22 forming a non-zero angle β with the axis 10, normal to the mean surface 110 of the first face 11. The glazing substrate 1 can advantageously be moved with respect to the magnetron 2, in a direction parallel or substantially parallel to the mean surface 110, as shown schematically by arrow 23, so that the particle beam 21 can be projected, in the same direction 22, onto the entire textured surface of the first face 11 of this glazing 1. 

[69] According to a feature of the invention, the angle of inclination β of the magnetron 2 is chosen so that the direction 22 of the beam 21 is closer to the direction normal to some of the surface segments of the textured surface, and further away from the direction normal to some of the other surface segments of the textured surface. In the embodiment shown, for example, the magnetron 2 is configured so that the beam 21 has a direction very close to the axis 102 normal to the second surface segments 112, and conversely forms an angle close to a right angle with the axis 101 normal to the first surface segments 111. 

[70] For example, the direction 22 of the beam 21 may form an angle of less than 10° with the direction normal to some of the surface segments of the textured surface, and an angle of more than 80° with the direction normal to some of the other surface segments of the textured surface. 

[71] As a result of this inclination, the particles contained in the beam 21 can be deposited without difficulty on the second surface segments 112. On the contrary, these particles have little chance of settling on the surface segments 111. As a result, the thickness of the functional coating layer 3 obtained differs depending on the orientation of the surface segments. 

[72] In this way, the functional coating layer 3 is advantageously thicker on the surface segments with an orientation normal to the direction 22 of the beam 21. On the contrary, the thickness of the functional coating layer decreases as the angle between this direction 22 of the beam 21 and the direction normal to the orientation of the surface segments increases. The thickness of the functional coating layer is thus very low, or even virtually zero, when the direction normal to the orientation of the surface segments is parallel to this direction 22 of the beam 21. 

[73] Figure 3 schematically shows a portion of the glazing substrate 1 after it has received a functional coating layer by such a method. On the first face 11 of this glazing substrate 1, the surface segments 112, whose normal direction corresponds to the axis 102, are covered by a functional coating layer 32 of maximum thickness. The axis 102, which is normal to the surface segments on which the thickness of the functional coating layer is at its maximum, corresponds to a direction referred to hereinafter as the "dominant direction" of the functional coating layer. In contrast, the surface segments 111, whose normal direction corresponding to the axis 101 forms a large angle with the dominant direction of the functional coating layer, are covered by a functional coating layer 31 of much smaller thickness. 

[74] In the embodiment shown, the thickness of the functional coating layer 32 on the surface segments 112 is thus at least twice, preferably at least four times, even at least six times or more than ten times greater than the thickness of the functional coating layer 31 on the surface segments 111. 

[75] Typically, the dominant direction of the functional coating layer, which is normal to the surface segments on which the thickness of the functional coating layer is maximum, is close to the direction of the beam 21 of the magnetron 2, when applying the functional coating layer to the first face 11 of this glazing substrate 1. 

[76] Of course, the different textured surface segments can have different orientations, and the magnetron 2 can also be oriented differently, to achieve a different distribution of the coating layer thickness between the surface segments with different orientations. 

[77] Thus, for example, the first face 61 of the glazing substrate 6 of Figures 6 to 8 can be covered with a functional coating layer that is deposited by sputtering, by a magnetron projecting a beam oriented in a direction 26, forming a non-zero angle β with the axis 60. 

[78] As a result of this beam orientation, the thickness of the functional coating layer is variable, depending on the surface segments. Some of these surface segments, with an orientation normal to a direction called the "dominant direction" of the functional coating layer, have a coating layer of maximum thickness. This dominant direction of the coating layer generally corresponds to the direction 26 of the magnetron beam that applied the functional coating layer. 

[79] In the example shown in Figures 6 to 8, this dominant direction is parallel to the axis 602, substantially normal to the second surface segments 612. These second surface segments 612 therefore have an orientation normal, to within 5°, to the dominant direction, and are covered by a relatively thick functional coating layer 3. 

[80] On the contrary, the first surface segments 611 have a normal orientation forming an angle greater than 55° with the dominant direction. These first surface segments 611 are covered by a functional coating layer 3, which is much thinner than the second coating segments. By way of example, this thickness may be at least twice, preferably at least four times, even at least six times or more than ten times greater on the second surface segments 612 than on the first surface segments 611. 

[81] It is considered that the invention can be usefully carried out as long as some of the surface segments, having a first orientation, are coated with a functional coating layer whose thickness is at least double the thickness of this same functional coating layer on some of the other surface segments, having a second orientation. 

[82] Figure 2 shows a possible embodiment of a device for applying a coating layer of differing thickness to different surface segments of the textured surface, depending on the orientation of these surface segments. A person skilled in the art would of course be able to imagine other ways of achieving the same result. 

[83] For example, the coating may be applied to the textured surface in multiple steps. In this case, a first step can allow a functional coating layer to be deposited to cover the entire textured surface with a functional coating layer of substantially uniform thickness. Such a deposition can, for example, be achieved by a non-directional thin-film deposition method, such as a chemical vapor deposition method well known to a person skilled in the art, or by a directional deposition method applied in a direction substantially normal to the mean surface of the textured surface. 

[84] A second step can then be implemented, aiming to at least partially remove this functional coating layer on some of the surface segments of the textured surface, depending on their orientation. This second step may, for example, be implemented by etching, performed by a directional ion source oriented in a direction forming a non-zero angle with the direction normal to the mean surface of the textured surface, closer to the direction normal to first surface segments than to the direction normal to second surface segments. 

[85] Such etching has the effect of at least partially removing the functional coating layer from the textured surface, this removal being much greater on the first surface segments, whose normal direction is close to the direction of the ion source beam, than on the second surface segments, whose normal direction is further away from the direction of the ion source beam. 

[86] This makes it possible to obtain a functional coating layer of greater thickness on the second surface segments than on the first surface segments. This thickness of the functional coating layer on the second surface segments may, for example, be more than twice as great as the thickness of the coating layer on the first surface segments. 

[87] Once the coating has been applied, the glazing substrate 1 can be implemented to form a glazing. It can be used on its own, with the textured surface of its first face 11 remaining in contact with the air. However, in this case, the surface texture can cause blurring or distortion of the light beams, as the index jump between the glazing substrate 1 and the air takes place at an irregular surface. 

[88] Figure 4 shows another example of a glazing that can be implemented with the glazing substrate 1. The glazing 4 shown is a composite glazing comprising the glazing substrate 1, whose non-textured second face 12 forms one face of the glazing 4. The first face 11 of the glazing substrate 1, whose textured surface is coated with the coating, is covered by a transparent index layer 41. This index layer 41 is made, for example, of a polymeric material, such as a polyvinyl butyral (PVB) film, or a sol-gel material. It can be applied in the form of a film, for example by a lamination method, or advantageously deposited on the face 11 in liquid form, for example in the form of a solution of sol-gel precursors, monomers or a resin, before being subsequently cured. It thus perfectly matches the protrusions of the textured surface of the first face 11 of the glazing substrate 1. 

[89] Advantageously, this index layer 41 has an optical index very close to that of the glazing substrate 1. In this way, the passage of a light beam from the glazing substrate 1 to the index layer 41, or vice versa, does not generate an index jump. The index layer 41 thus has the effect of compensating for the texture of the first face 11 of the glazing substrate 1, so as to obtain a smooth surface. Under these conditions, the textured surface of the first face 11 of the glazing substrate 1 generates no blurring or distortion of the light rays passing through the glazing 4. This glazing 4 can thus be used as a transparent flat glass. 

[90] However, this glazing 4 has a special feature, due to the distribution of the functional coating layer on the glazing substrate 1. In this way, the incident light passing through the glazing 4 in a direction close to the dominant direction of this functional coating layer, represented by the arrow 40, on average passes through a greater thickness of this functional coating layer than the incident light passing through the glazing 4 in a direction further away from the dominant direction represented by the arrow 40. This feature of the glazing 4 can advantageously appear on all glazings using a glazing substrate according to one embodiment of the invention. 

[91] In the embodiment shown, the index layer 41 is sandwiched between the glazing substrate 1 and a second glazing substrate 42, which may for example be a sheet of glass or any other material commonly used to make glazing substrates. This second glazing substrate 42 can form the second face of the glazing 4. 

[92] A glazing according to the invention can be used, for example, to form a wall of a building or a vehicle. This glazing advantageously has different light transmission properties depending on the orientation of the incident light rays. 

[93] Figure 5, for example, shows the glazing 4 used as a wall to separate an interior space 501 from an exterior space 502. This glazing 4 is arranged vertically, so that the direction normal to this glazing is horizontal. This glazing 4 is advantageously arranged in such a way that the dominant direction, represented by the arrow 40, of its functional coating layer forms an angle of elevation of about 45° with the horizontal. This functional coating layer is selected, in this embodiment, to absorb infrared radiation. 

[94] When the sun is high in the sky, for example in the position represented by the pictogram 51, the solar radiation represented by the arrow 511 arrives on the glazing 4 with an orientation, measured by the angle of elevation δ1, which is close to the orientation of the dominant direction, represented by the arrow 40, of the functional coating layer. To pass through the glazing 4, solar radiation must pass through a significant average thickness of the functional coating layer. 

[95] When the sun is high in the sky, the radiation it emits is generally strong, and in particular comprises a significant proportion of high-energy radiation, such as infrared rays. The passage of solar radiation, shown schematically by arrow 511, through the thick functional coating layer 32 causes these functional coating layers 32 to absorb a large proportion of the infrared radiation. The radiation shown schematically by the arrow 512, coming from the sun in the high position and having passed through the glazing 4, is therefore highly filtered radiation, having lost a large part of its infrared components and therefore having a much lower energy. In such conditions, the glazing 4 therefore protects the interior space 501 from excessive heating due to solar radiation. 

[96] When the sun is lower in the sky, for example in the position represented by the pictogram 52, the solar radiation represented by the arrow 521 arrives on the glazing 4 with an orientation, measured by the angle of elevation δ2, which is much closer to the horizontal direction normal to the glazing 4, and further away from the orientation of the dominant direction, represented by the arrow 40, of the functional coating layer. To penetrate the glazing 4, solar radiation must pass through a thickness of the functional coating layer, which is, on average, smaller. This functional coating layer absorbs only a relatively small proportion of the infrared radiation contained in the radiation shown schematically by the arrow 521. The radiation shown schematically by the arrow 522, resulting from the passage of the radiation shown by the arrow 521 through the glazing 4, is therefore only slightly filtered, compared with the radiation shown by the arrow 521. 

[97] As a result, when the sun is high in the sky and it is necessary to protect the interior space 501 from the heat of solar radiation, the glazing absorbs a large proportion of the energy from this solar radiation, whereas when the sun is low in the sky and it is useful to heat the interior space 501 with solar radiation, it allows a relatively large proportion of the energy from this solar radiation to pass through. 

[98] Thus, the inventors have tested a glazing, similar to the glazing 4 shown in Figures 4 and 5, in which a functional coating layer is deposited on the textured surface of a glazing substrate, in a dominant orientation forming a 45° angle of elevation with the horizontal. This functional layer is made of a Nickel-Chromium alloy, known for its solar radiation energy-absorbing properties, and has a thickness of 50 nm on the surface segments normal to its dominant direction. 

[99] This glazing has an energy transmission coefficient TE0° = 0.35 for incident solar radiation in a normal direction to the plane of the glazing. Conversely, this energy transmission coefficient is reduced:- at TE30° ≈ 0.25 for solar radiation that is incident in a direction forming an angle of elevation of 30° to the horizontal, approaching the dominant direction of the coating layer,- at TE45° ≈ 0.1 for solar radiation that is incident in a direction forming an angle of elevation of 45° to the horizontal, parallel to the dominant direction of the coating layer, and- at TE60° ≈ 0 for solar radiation that is incident in a direction forming an angle of elevation of 60° to the horizontal. 

[100] By comparison, a similar glazing substrate homogeneously coated with a 50 nm-thick Ni-Cr absorbent layer has a TE of 0 at any angle of incidence. 

[101] The dominant direction of the functional coating layer can advantageously be oriented such that the effect of this functional coating layer is variable, not only depending on the angle of elevation of the incident radiation, but also, or even exclusively, depending on the angle of azimuth of this incident radiation, with respect to the direction normal to the plane of the glazing. Thus, for example, the dominant direction of a functional coating layer absorbing solar radiation energy can be chosen so that the glazing absorbs a greater proportion of this solar radiation when this radiation comes from a direction closer to the South, and a smaller proportion when this radiation comes from a direction further away from the South. 

[102] More generally, a glazing according to the invention can have features such as transmission, absorption and / or reflection of radiation which vary according to the orientation of the incident radiation. 

[103] A person skilled in the art would be able to imagine numerous variants of such a solution. It is thus possible, for example, to produce a glazing comprising a substrate, one textured face of which is covered with multiple functional layers of coatings, each of the layers being deposited in such a way as to have a different dominant direction and different characteristics. 

[104] Some of the surface segments of this substrate, having a first orientation, can thus be covered predominantly by a coating layer with a first property, while other surface segments of this substrate, having a second orientation, can be covered predominantly by a coating layer with a second property. In this way, the glazing can have certain properties, such as transmission, reflection and / or absorption, for incident radiation at certain inclinations, and other properties for incident radiation at other inclinations. 

[105] In the embodiments described above, it is provided that the entire surface of the first face of the glazing substrates is homogeneously textured. It is also possible for this surface texturing to be carried out only on part of the face of the glazing substrate, or for this texturing to have different characteristics in different areas of the face of the glazing substrate. In such a case, the properties of the glazing, e.g., transmission, reflection and / or absorption, can be different depending on the areas of the glazing substrate. 

[106] Similarly, in the embodiments described above, it is intended that the functional coating layer(s) be applied to the textured surfaces in a homogeneous manner. It is also possible for these coating layers to be applied to only part of the face of the glazing substrate, or for the characteristics of these coating layers, for example their thickness or dominant orientation, to vary according to the areas of the face of the glazing substrate. In such a case, the properties of the glazing, e.g., transmission, reflection and / or absorption, can be different depending on the areas of the glazing substrate.

Claims

1. A coated glazing substrate (1, 6), suitable for being incorporated into a glazing (4), said substrate having at least a first face (11, 61), said first face having a mean surface (110, 610) normal to a main normal direction (10, 60), said first face (11, 61) being textured so as to have at least:- first surface segments (111, 611) with an orientation normal to a first normal direction (101, 601), which forms an angle (α1, α3) of more than 10° with said main normal direction (10, 60),- second surface segments (112, 612) with an orientation normal to a second normal direction (102, 602), which forms- an angle (α2, α4) of more than 10° with said main normal direction (10, 60), and- an angle of more than 20° with said first normal direction (101, 601),said first face (11, 61) being at least partially covered with a coating comprising at least one first functional layer (3),characterized in that the thickness of said functional layer (32) on said second surface segments (112, 612) is greater than twice the thickness of said functional layer (31) on said first surface segments (111, 611).

2. The glazing substrate according to the preceding claim, characterized in that said functional layer (3) has light absorption and / or solar radiation reflection characteristics.

3. The glazing substrate according to any one of the preceding claims, characterized in that said first face (61) has at least third surface segments, oriented in directions distinct from the orientation directions of said first surface segments (611) and said second surface segments (612), said first, second and third surface segments being covered by said functional layer (3), the thickness of which is variable based on the orientation of each of said surface segments.

4. The glazing substrate according to any one of the preceding claims, characterized in that said coating comprises at least one second functional layer, the thickness of which is variable depending on the orientation of each of said surface segments (111, 112, 611, 612).

5. The glazing substrate according to any one of the preceding claims, characterized in that said first face (11, 61) is textured so as to have protrusions whose “peak-to-valley” height is between 0.5 and 150 μm.

6. The glazing substrate according to any one of the preceding claims, characterized in that said first face (11) is textured so as to have protrusions forming repeated or even periodic patterns, each pattern comprising at least one of said first surface segments (111) and at least one of said second surface segments (112).

7. The glazing substrate according to any one of claims 1 to 5, characterized in that said first face (61) is textured so as to have a random shape, comprising said surface segments (611, 612).

8. The glazing substrate according to any one of the preceding claims, characterized in that said first functional layer (3) is at least 10 times thicker on said second surface segments (112, 612) than on said first surface segments (111, 611).

9. The glazing substrate according to any one of the preceding claims, characterized in that the thickness of said functional layer (3) is maximum on at least one of said surface segments (112, 612), normal to a so-called "dominant" direction,and in that said thickness of said functional layer (3) on each of said other surface segments (111, 611) decreases as the angle between said dominant direction and the direction normal to said surface segment increases.

10. The glazing substrate according to any one of the preceding claims, characterized in that said functional layer (3) is selected from metal layers based on a metal or metal alloy, metal nitride layers and metal oxynitride layers.

11. A glazing characterized in that it comprises a glazing substrate (1) according to any one of claims 1 to 10, and a transparent layer (41) with an optical index substantially identical to the optical index of said glazing substrate (1), pressed against said first face (11) of said glazing substrate (1).

12. A method for manufacturing a coated glazing substrate, characterized in that it comprises a step of applying at least one functional coating layer (3) to a first face (11, 61) of a glazing substrate (1, 6),said first face (11, 61) having a mean surface (110, 610) normal to a main normal direction (10, 60),said first face (11, 61) having a textured surface with surface segments (111, 112, 611, 612) having different orientations,said step of applying at least one functional coating layer comprising projecting said coating (3) onto said first face (11, 61) by a directional deposition method, wherein the material constituting said functional coating layer (3) is projected onto said face (11, 61) along a determined direction (22, 26),characterized in that said determined direction (22, 26) forms:- an angle greater than 20° with said main normal direction (10, 60) of said first face (11, 61),- an angle greater than 40° with the normal direction (101, 601) to some of said surface segments, and- an angle of less than 20° with the normal direction (102, 602) to some others of said surface segments (112, 612).

13. The manufacturing method according to the preceding claim, characterized in that said directional deposition method is a magnetron sputtering method (2). 

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