Screen printing stencil for the production of glazing units with electrically conductive patterns

Description

[0001] The present invention relates to the field of printing electroconductive patterns, in particular silver-based, on glazing.

[0002] Electrically conductive patterns, such as heating wires, antennas or other sensors present in automotive glazing, are made from a conductive paste, for example a silver paste screen-printed on a sheet of glass, and are connected to an electrical power system via connectors soldered to the conductive paste. The connectors are soldered in certain well-defined areas of the glazing and the alloys currently used to make these solders are lead-free alloys, for example based on silver, tin and copper.

[0003] In order to be placed on the market and accepted by car manufacturers, glazing equipped with such electrically conductive devices must successfully pass increasingly stringent resistance tests. The alloys used for welding must, in particular, meet the criteria imposed by the TCT test (or " température cycling test »). The objective of this test is to determine whether the glazing, once equipped with electrical functions, can withstand successive and rapid increases and decreases in temperature without being weakened. These tests were developed in order to accelerate the effects that would be caused by the differences in thermal behavior of the various components of the system. The new test requires temperature variations between -40°C and +105°C, therefore over a wider variation range than the previous tests which were limited to 90°C. The number of cycles has also been modified since it has increased from 10 cycles to a minimum of 60 cycles. The new TCT conditions also require that these temperature variations be carried out under a voltage of 14 V during the temperature increase phases, which leads to additional heating and corresponds to local temperatures that can reach approximately 120°C.To successfully pass these tests, it was necessary to increase the thickness of the electrically conductive patterns, particularly in the soldering areas, where the connectors are placed and where the soldering with the lead-free alloy is carried out. In automotive glazing, the connection or soldering areas are generally made at the collector strips (also called "bus bars" in English terminology) located on either side of the heating network, in the lateral parts of the glazing, but can also be done in more central parts.

[0004] It is known to screen print in a single step electroconductive patterns of different thickness between the central part and the lateral parts, using a single printing fabric (or screen), the mesh size of which varies according to the zones and allows patterns of different thicknesses to be printed. These fabrics allow in particular to deposit on the lateral parts of the glazing thicker thicknesses of paste at the level of the collector strips, while keeping in the central part thin and barely visible electroconductive tracks. Thus, the thickness is sufficiently large at the places where the connections and welds are made, but sufficiently low in the central part so as not to hinder visibility. This type of fabric with variable mesh size does not, however, allow to obtain simultaneously, in the central part of the glazing, fine patterns and thicker patterns.However, some soldering points, particularly at the antenna buttons, are often positioned in the center of the printed heating networks, in the lower or upper areas of the central part of the glazing. To obtain an electroconductive pattern of greater thickness in certain areas of the central part of the glazing, it is possible to carry out double screen printing since the variable mesh size screens only allow for large thicknesses in the lateral parts, on the edges of the glazing. Thus, to obtain greater thicknesses in the central part of the glazing, a first printing pass is carried out by screen printing the electroconductive paste, then the paste is dried before carrying out a second printing pass identical to the first at a second printing station.This technology therefore requires heavy investment, since at least an IR drying device and a second printing station are required. In some cases, if the required thickness is even greater, it may be necessary to carry out a third screen printing step, also with intermediate drying.

[0005] We are therefore seeking to develop a simplified, less expensive process, making it possible to produce thick electrically conductive patterns at any desired location and in particular, in the central part of a substrate, away from the collector strips.

[0006] A solution, proposed by application WO2018 / 229449, consists in using a screen printing screen comprising a main screen and on an area, located in the central part, at least one secondary screen fixed on one face of said main screen, the mesh of the secondary screen being wider than the mesh of the main screen in said central part, and the mesh of the secondary screen forming with the mesh of the main screen an angle α of between 1 and 89°. Such a screen makes it possible to obtain in a single screen printing pass glazings having in their central part thin electrically conductive tracks and, at the double screen area, therefore also in the central part of the glazing, particularly thick electrically conductive patterns, for example welding zones for antenna buttons.

[0007] This solution is not without its drawbacks, however, in particular that it does not allow additional thickness to be obtained in certain specific areas of the side parts. It also does not allow the thickness of the electrically conductive tracks in the soldering areas and in other areas to be adjusted completely independently. It is therefore not always possible to achieve the desired thicknesses in the soldering areas while respecting the specifications in terms of network resistance.

[0008] Application WO2019206592 proposes using, for printing in the welding zones, at the collector strips, a screen printing screen having in these zones closed parts in the form of networks of dots or lines. The manufacture of the screen implements, in these zones, a second coating with photocrosslinkable resin and a second exposure step, which complicates the process. It has also been observed that the excess coating thickness was progressively reduced during use of the screen due to the pressure exerted by the doctor blade. The lifespan of the screen is then reduced. Application US2016129685 also describes a process in which a second exposure step makes it possible to locally create an excess thickness, more particularly in the shape of a honeycomb.

[0009] The invention aims to overcome these drawbacks.

[0010] To this end, the invention relates to a method for manufacturing a screen printing screen for obtaining glazing provided with electrically conductive patterns, comprising the following steps: a) coating a sieve with a photocrosslinkable emulsion, then b) drying the sieve thus coated, then c) applying a photocrosslinkable self-supporting film to at least one area, called a film area, of one face of the coated sieve, then d) exposing the coated sieve in order to crosslink the photocrosslinkable emulsion and the or each photocrosslinkable self-supporting film in predetermined areas called crosslinking areas, the crosslinking areas in at least part of the or each film area being in the form of a network of dots or lines, then e) washing the coated sieve in order to remove the emulsion and the or each self-supporting film in areas other than the crosslinking areas.

[0011] Another subject of the invention is a screen printing screen, for obtaining glazing provided with electrically conductive patterns, in particular obtained by this method. This screen comprises a sieve, part of the meshes of which are closed by photocrosslinked material in zones called crosslinking zones, said sieve comprising at least one zone called film zone such that the crosslinking zones located in the or each film zone are in the form of a network of points or lines, and the thickness of photocrosslinked material closing the meshes of the sieve is greater in the crosslinking zones located in the or each film zone than in the crosslinking zones located outside the film zones.

[0012] Another subject of the invention is a method for obtaining glazing, comprising a glass sheet coated on one of its faces with electroconductive patterns having in at least one zone, called the excess thickness zone, a greater thickness than in the other zones, said method comprising screen printing of said electroconductive patterns in a single pass, according to the following steps: the positioning of a screen printing screen according to the invention opposite a sheet of glass, so that the or each film zone of said screen printing screen is opposite a zone of the glass sheet intended to become an excess thickness zone, then the deposition, in particular using a doctor blade, on the screen printing screen, of an electroconductive paste, then a heat baking treatment.

[0013] The invention finally relates to a glazing obtained, or capable of being obtained, by the method described above. This glazing comprises a glass sheet coated on one of its faces with electrically conductive patterns having in at least one zone, called the excess thickness zone, a greater thickness than in the other zones.

[0014] The screen obtained according to the invention makes it possible to obtain, in the areas of the glazing corresponding to the film areas of the screen, thicker electrically conductive patterns. The process for manufacturing the screen is also simplified, because it does not require a second exposure, and the screen obtained is more durable, because the film area (and therefore the excess thickness of photocrosslinked material) being placed opposite the glazing during screen printing, it is not likely to be damaged by the doctor blade.

[0015] The screen thus makes it possible in particular to obtain glazing comprising patterns comprising thin electrically conductive tracks, for example a network of heating wires (in particular at the camera zone), an alarm network, antennas or collector strips, and welding zones of greater thickness which can be located both in the central part and in the lateral parts of the glazing, for example welding zones for antenna button located in the central part and heating network welding zones located in the lateral part in contact with the collector strips.

[0016] The areas of excess thickness are not necessarily limited to the welding areas. The invention also advantageously makes it possible to thicken certain areas of the collector strips, in particular near the welding areas, in particular to avoid undesirable heating.

[0017] The screen mesh can be made of any material known for making screen printing screens, for example polyester or polyamide.

[0018] A screen printing screen is traditionally obtained by coating a photocrosslinkable emulsion on at least part of the surface of a screen, drying the screen, exposing the screen to crosslink the photocrosslinkable emulsion in predetermined areas, then washing and drying the screen.

[0019] The coating is preferably done on both sides of the sieve, over its entire surface.

[0020] The photocrosslinkable emulsion makes it possible to selectively seal the meshes of the sieve in the areas subject to exposure, the washing step then serving to eliminate the emulsion in the areas not subject to exposure, therefore in the parts where the meshes must remain unsealed and through which the printing paste must pass during screen printing to coat the glass sheet and form the electroconductive patterns.

[0021] According to the invention, a self-supporting photocrosslinkable film is applied to at least one area called the "film area" of one face of the screen. This film makes it possible to locally add an excess thickness of photocrosslinkable material in specific areas of the screen, on one of its faces.

[0022] Such a film is commonly referred to in the art as a "capillary film." It generally takes the form of a film of a dried photocrosslinkable emulsion deposited on a polymeric sheet, particularly polyester.

[0023] The thickness of the photocrosslinkable self-supporting film is preferably between 25 and 100 µm, in particular around 50 µm.

[0024] Application is preferably carried out after removing the polymer sheet and moistening the film, so as to allow satisfactory adhesion of the film to the coated and dried sieve. To do this, it is possible, for example, to soak the film in water for a few seconds. After this moistening step, the surface of the film has sufficient adhesion to the coated and dried sieve.

[0025] Preferably, the screen comprises several film zones. These zones will correspond on the glazing to the extra thickness zones, therefore in particular, but not necessarily only, to the welding zones. Film zones are therefore preferably located at least in the lateral parts of the screen, and preferably also in the central part. The total surface area of ​​the film zones preferably occupies between 0.1 and 10%, in particular between 0.5 and 5%, of the surface area of ​​the screen.

[0026] The exposure step is the step during which the photocrosslinks the emulsion, generally under the effect of ultraviolet radiation. This step is preferably carried out by placing against the screen (advantageously on the side of the face bearing the film(s)) a slide comprising a transparent support, typically made of polyester, coated with patterns of an ink opaque to ultraviolet radiation, corresponding to the electroconductive patterns to be printed on the glazing, then irradiating said slide by means of ultraviolet radiation. The emulsion is therefore crosslinked and closes the meshes of the sieve only in the parts of the screen, called crosslinking zones, located under the parts of the slide not covered with ink. In the other parts, the emulsion is not crosslinked and is removed during the washing step, leaving the meshes open, so that the paste can pass through them during screen printing.The patterns shown on the slide are thus found on the glass.

[0027] According to the invention, the crosslinking zones in at least a portion (in particular in at least 50%, or at least 75%, or even all) of the or each film zone are in the form of a network of points or lines. It is recalled that these crosslinking zones correspond on the screen to the zones where the meshes are closed. The slide therefore has the same network, but reversed. In the case of the film zones, the meshes are closed by the material originating both from the emulsion added in the coating step a) and from the self-supporting film applied in step c). The thickness of photocrosslinked material closing the meshes is therefore greater in the film zones than in the other zones.

[0028] The dot network consists of dots periodically arranged in rows and columns. The line network consists of regularly spaced lines.

[0029] The points in the dot grid can be of any shape. They are preferably rectangular, square, elliptical, or circular. Best results are achieved with circular points.

[0030] Preferably, the dots of the dot array have a maximum lateral dimension ranging from 0.10 to 0.30 mm, or the lines of the line array have a width ranging from 0.10 to 0.40 mm. In the case of circular dots, the maximum lateral dimension is the diameter of the circular dot. Preferably, the ratio R1 between the distance separating the centers of the dots of the dot array (in a row or a column) and the maximum lateral dimension of the dots is between 1 and 3, in particular between 1.5 and 2.5, or even between 1.9 and 2.1. In the case of a line array, the ratio R2 between the distance separating the centers of the lines and the width of the lines is between 0.7 and 2.5, in particular between 0.8 and 1.2.Such very small dimensions are lower than the usual resolution of screen printing, and are advantageous in that they do not allow for perfectly consistent printing: in other words, a certain thickness of electroconductive paste is deposited even under the crosslinking zones. To the naked eye, the printing in the excess thickness zone, corresponding to the film area on the screen, is continuous and homogeneous, and does not present a network of dots or lines. Only microscopic observation reveals a slight texturing, the thickness of the deposited paste being slightly lower in the areas corresponding to the crosslinking zones. The overall (or average) thickness in the excess thickness zone is, however, higher than in the other areas of the glazing.

[0031] According to one embodiment, the sieve has an identical mesh size at all points. For example, it is possible to choose, for the sieve, 90 wires per cm for wire diameters of 40 to 48 µm. More generally, the number of wires per cm is preferably between 43 and 180, in particular between 77 and 150, and the diameter of the wires is preferably between 30 and 150 µm, in particular between 77 and 120 µm.

[0032] According to another embodiment, the sieve comprises a central portion and at least one side portion, the mesh size in the central portion being larger than the mesh size in the at least one side portion. In particular, the number of wires per cm in the central portion is larger than the number of wires per cm in the at least one side portion, and the diameter of the wires in the central portion is smaller than the diameter of the wires in the at least one side portion.

[0033] In the context of this embodiment, one can advantageously choose: in the central zone, 77 threads per cm for a diameter of 48 µm, 77 threads per cm for a diameter of 55 µm, 90 threads per cm for a diameter of 48 µm, in the or each lateral zone, 42 threads per cm for a diameter of 80 µm, 48 threads per cm for a diameter of 80 µm, 49 threads per cm for a diameter of 70 µm.

[0034] This type of screen allows, in particular, to deposit a greater thickness of electroconductive paste on the lateral parts, which correspond to the positioning of the collector strips (or bus bars), compared to the printing areas corresponding to the thinner wires of the heating network. Examples of this type of screen include the Vario ®< product from SEFAR or Variant ®< from SAATI, which allows, during the same printing, to obtain different thicknesses in different areas of the glazing.

[0035] Preferably, the screen is rectangular or substantially rectangular, and the central part corresponds to the rectangular part, extending over the entire length of the short sides of the screen, the mediator of the short sides of which corresponds to the mediator of the long sides of the screen, and which occupies 20 to 40% of the surface area of ​​the screen. The screen preferably comprises two lateral parts, corresponding to the two rectangular parts arranged symmetrically with respect to the mediator of the long sides of the rectangle, on either side of the latter, occupying 20 to 40% of the surface area of ​​the screen.

[0036] The electrically conductive patterns preferably comprise electrically conductive tracks located in at least one lateral portion and in a central portion of the glazing, the areas of excess thickness being located in said central portion and / or in at least one lateral portion. Preferably, the areas of excess thickness are located both in the central portion and in at least one lateral portion, and even in the lateral portions.

[0037] The electrically conductive tracks located in the central part are in particular heating wires, alarm films and / or antennas. The electrically conductive tracks located in a lateral part, in particular in two opposite lateral parts, are in particular collector strips.

[0038] Advantageously, the areas of excess thickness include welding areas, or even correspond to welding areas. The areas of excess thickness located in the central part are or include, for example, welding areas for connecting an antenna or alarm. The areas of excess thickness located in the lateral parts include, for example, welding areas for connecting a heating network. The latter are, for example, located on each of the collector strips.

[0039] The solder zones are areas on which a connector can be soldered in order to electrically connect the electrically conductive patterns. Thus, when the excess thickness zones encompass or correspond to solder zones, the method can therefore also comprise an additional step of soldering at least one connector on at least a portion of an excess thickness zone. The soldering is in particular carried out using a solder alloy.

[0040] The connector is preferably metallic, especially made of steel containing chromium. Soldering is carried out using a solder alloy that is preferably lead-free, especially based on tin, silver and copper.

[0041] The glass sheet is typically soda-lime glass, but may be other types of glass, for example borosilicate or aluminosilicate. Its thickness is preferably between 0.7 and 6 mm, especially between 1 and 4 mm. At least one dimension of the glass sheet is preferably at least 1 μm.

[0042] The glass sheet may be clear, or preferably tinted, for example green, gray or blue. To achieve this, the composition of the glass includes colorants, in particular iron oxide, in a total weight content (expressed as Fe 2 O 3 ) of between 0.05 and 2.1%, in particular between 0.1 and 1.0%.

[0043] The glass sheet is generally flat at the time of depositing the electrically conductive patterns. It is then preferably curved, normally during the heat treatment of baking the electrically conductive patterns. The final glazing is therefore preferably curved.

[0044] The face of the glass sheet on which the electroconductive patterns are deposited may have been previously partially coated with an enamel coating. In particular, a black enamel coating may have been deposited by screen printing on the periphery of the glass sheet and part of the electroconductive patterns (in particular the collector strips) is then deposited on the enamel coating. In this case, the method comprises, before the electroconductive patterns are deposited, a preliminary step of depositing by screen printing a black enamel coating on the periphery of the glass sheet, on which part of the electroconductive patterns is deposited. Such a coating makes it possible to conceal and protect against ultraviolet radiation the seals used for positioning and mounting the glazing in the bodywork bay. The enamel coating also makes it possible to conceal the collector strips.

[0045] The screen printing step is carried out by positioning the screen printing screen opposite the glass sheet and then depositing, in particular using a doctor blade, an electroconductive paste, in particular silver, on the screen printing screen. During the screen printing step, the film areas are arranged opposite the areas of the glass sheet intended to become areas of excess thickness. The expression "opposite" implies that the face of the screen where the photocrosslinkable self-supporting film has been applied is turned towards the glass sheet. In this way, the film area is not damaged by the doctor blade during screen printing.

[0046] The electrically conductive patterns are preferably formed from a silver paste.

[0047] Preferably, the electroconductive silver paste comprises in the wet state at most 88%, in particular at most 85% by weight of silver, for example from 75 to 85%, in particular from 80 to 84% by weight of silver. These pastes with a high silver content compared to the pastes usually used, are particularly suitable for lead-free solder alloys. These silver pastes require, to ensure good solderability and good resistance to the TCT test, to apply greater thicknesses in the solder zones, which becomes possible thanks to the method according to the present invention.

[0048] The lower the silver content of the paste, the greater the thickness of the patterns (of the first layer) in the wet state (before firing) must be for the same pattern thickness after firing. Thus, for a pattern thickness of 8 µm after firing, the thickness in the wet state is typically around 25 µm for a paste containing 80% silver by weight, and around 35 to 40 µm for a paste containing 75% silver by weight.

[0049] Preferably, the paste further comprises a solvent, an organic medium, intended to facilitate deposition by screen printing, and a glass frit, which after melting fixes the silver particles on the glass sheet.

[0050] The thickness of the electrically conductive patterns in the or each area of ​​excess thickness is preferably at least 8 µm, in particular between 10 and 20 µm, or even between 10 and 15 µm, after the baking heat treatment step. Such a thickness makes it possible to meet the requirements of the TCT test.

[0051] The thickness of the patterns in the areas other than the excess thickness areas is preferably at most 8 µm, in particular between 3 and 7 µm.

[0052] The glazing may or may not be dried after the paste is applied. The glazing then undergoes heat treatment to cure the electrically conductive paste. This heat treatment is typically a bending and / or tempering process. Bending can be carried out, for example, by gravity (the glass deforms under its own weight) or by pressing, at temperatures typically ranging from 550 to 720°C.

[0053] The glazing obtained is in particular a rear window of a motor vehicle, a side window of a motor vehicle or even a windshield of a motor vehicle.

[0054] Electrically conductive patterns include antennas, collector strips, alarm wires, and / or heating wires. The collector strips are preferably located in the two opposite side portions of the glazing. The heating wires are preferably located mainly in the central portion of the glazing, and extend parallel to the long edge of the glazing between the two collector strips. This is particularly the case for a rear window.

[0055] Preferably, the or each area of ​​excess thickness includes or is a welding area for connection of an antenna and / or heating network and / or alarm.

[0056] In the case of a windshield, electrically conductive patterns include antennas. Electrically conductive patterns can also be heating wires that provide local heating in camera windows, for example, to detect the distance to the vehicle ahead.

[0057] In the case of side glazing, electrically conductive patterns include antennas or alarm wires.

[0058] The invention will be better understood in light of the following exemplary embodiments, illustrated by the Figures 1 à 3 . [ Fig.1 ] represents a screen printing screen according to the invention. [ Fig.2 ] represents a film area. [ Fig.3 ] represents a glazing obtained according to the invention, in the example a rear window of a motor vehicle.

[0059] The screen printing screen 100 schematically represented in [ Fig.1 ] comprises a rectangular sieve 101 on the surface of which photocrosslinkable self-supporting films have been applied in film areas 102, 104 and 106. The areas of the sieve 101 in which the meshes are closed (crosslinking areas) are shown in gray, while the areas in which the meshes are not closed are shown in white. These unclosed areas draw a pattern which will correspond in the final glazing to the areas in which the electrically conductive patterns will be deposited.

[0060] There [ Fig.2 ] schematically represents one of the film zones, zone 102. After exposure by means of ultraviolet radiation, the film zone 102 has a crosslinking zone, therefore a zone where the meshes of the sieve are blocked, schematically represented in black. This crosslinking zone is in the form of a network of points 108. By way of non-limiting example, these points are here circular and have a diameter of 0.2 mm, the distance separating the centers of the points being 0.4 mm. The size of the points is therefore deliberately exaggerated in the figure in order to allow their visualization. The zone represented in white corresponds to the zones where the meshes of the sieve 101 are not blocked.

[0061] The presence of these film zones 102, 104 and 106 on the screen made it possible to obtain zones of excess thickness on the glazing 1 represented in [ Fig.3 ]. As explained previously, the areas of excess thickness were obtained by placing the film areas of the screen 100 opposite them during the screen printing step.

[0062] In this [ Fig.3 ], the glazing 1 comprises a glass sheet 2 having a central part A and two lateral parts C. In these parts A and C have been printed electroconductive patterns 4, 6, 8, 10, more precisely a network of horizontal and vertical heating wires 4, connected in the lateral parts C to collector strips 8, an antenna 6, a welding zone for antenna button 10. In each lateral part C the collector strips 8 comprise a welding zone 12 for supplying the heating network. The position of the welding zones 12, in the lower part of the collector strips 8, is shown diagrammatically in the figure by dotted lines.

[0063] The wires 4, 6, the collector strips 8, as well as the antenna button 10 were printed by screen printing a silver paste (comprising for example 80% by weight of silver) on the glass sheet 2.

[0064] Certain zones 10A, 12A, shown in darker color, are areas of excess thickness. Zone 10A is an area corresponding to a welding area for connecting the antenna 6. Zones 12A are areas located on the collector strips 8 and include the welding areas 12 for connecting the heating network.

[0065] In a preliminary step, a black enamel coating (not shown) was deposited by screen printing on the periphery of the glass sheet 2, in the form of a peripheral strip. Certain electrically conductive patterns, in particular the collector strips 8, were therefore deposited on this enamel coating.

[0066] The electrically conductive patterns have a greater thickness in the 10A and 12A overthickness zones than in the other zones.

[0067] The excess thickness zones 12A are here wider than the welding zone 12 itself, and therefore “extend” beyond this zone, in order to avoid undesirable heating in the zones located near the welding zone. In another embodiment, the excess thickness zones 12A can correspond exactly to the welding zones 12.

[0068] The glass sheet then underwent a bending heat treatment at a temperature of approximately 620°C, during which the first and second layers were also fired.

[0069] After baking, the thickness in the 10A and 12A overthickness zones was typically in the order of 10 to 15 µm. In the other zones the thickness was 8 µm.

Claims

1. A method of manufacturing a screenprinting screen (100) for obtaining glazings provided with electroconductive patterns, comprising the following steps: a) coating a mesh (101) with a photocrosslinkable emulsion, then b) drying the mesh (101) thus coated, then c) applying a self-supported photocrosslinkable film on at least one area, called film area (102, 104, 106), on one face of the coated mesh (101), then d) insolating the coated mesh (101) in order to cross-link the photocrosslinkable emulsion and the, or each, self-supported photocrosslinkable film in predetermined areas called cross-linking areas, the cross-linking areas in at least a portion of the, or each, film zone being in the form of a network of points (108) or lines, then e) washing the coated mesh to eliminate the emulsion and the, or each, self-supported film in the areas other than the cross-linking areas.

2. The method according to the preceding claim, wherein the film areas are located at least in the lateral portions of the screen, and also preferably in the central portion.

3. The method according to one of the preceding claims, wherein the thickness of the self-supported photocrosslinkable film is between 25 and 100 µm.

4. The method according to one of the preceding claims, wherein the points (108) of the points network have a maximum lateral dimension ranging from 0.10 to 0.30 mm, or the lines of the line network have a width ranging from 0.10 to 0.40 mm.

5. The method according to the preceding claim, wherein the ratio R1 between the distance separating the centers of the points (108) of the points network and the maximum lateral dimension of the points (108) falls between 1 and 3.

6. A screenprinting screen (100) for obtaining glazings provided with electroconductive patterns obtained by the method according to one of the preceding claims, said screen (100) comprising a mesh (101) a portion of the apertures of which are blocked by photocrosslinked material in areas called cross-linking areas, said mesh (101) comprising at least one area (102, 104, 106) called film area such that the cross-linking areas located in the, or each, film area are in the form of a network of points (108) or lines, and the thickness of photocrosslinked material blocking the apertures of the mesh is greater in the cross-linking areas located in the, or each, film area than in the cross-linking areas located outside the film areas.

7. A method of obtaining a glazing (1) comprising a sheet of glass (2) coated on one face thereof with electroconductive patterns (4, 6, 8, 10) having in at least one area (1 0A, 12A), called extra thickness area, a greater thickness than in the other areas, said method comprising the screen-printing of said electroconductive patterns in a single run, according to the following steps: - positioning a screenprinting screen (100) according to the preceding claim facing a glass sheet (2), in such a way that the, or each, film area (102, 104, 106) of said screenprinting screen is facing an area of the glass sheet (2) intended to become an extra thickness area (10A, 12A), then - depositing, particularly by means of a squeegee, on the screenprinting screen (100), an electroconductive paste, then - firing heat treating.

8. The method according to the preceding claim, wherein the electroconductive patterns (4, 6, 8, 10) comprise electroconductive tracks (4, 6, 8) located in at least one lateral portion (C) and in a central portion of the glazing (A), with the extra thickness areas (10A, 12A) being located in said central portion (A) and / or in at least one lateral portion (C), the extra thickness areas (10A, 12A) preferably being located in the central portion (A) and in the lateral portions (C).

9. The method according to one of claims 7 or 8, comprising, before the deposition of the electroconductive patterns, a prior step of depositing by screenprinting a black enamel coating at the edge of the glass sheet (2), on which part of the electroconductive patterns (6, 8, 10) is deposited.

10. The method according to one of claims 7 to 9, wherein the electroconductive patterns (4, 6, 8, 10) are formed from a silver paste, particularly comprising, in the wet state, at most 88% by weight of silver.

11. The method according to one of claims 7 to 10, wherein the thickness of the electroconductive patterns (8, 10) in the, or each, extra thickness area (10A, 12A) is at least 8 µm, in particular between 10 and 20 µm, and the thickness of the patterns (4, 6, 8) in the areas other than the extra thickness areas is at most 8 µm, particularly between 3 and 7 µm, after the firing heat treatment step.

12. The method according to one of claims 7 to 11, wherein the extra thickness areas (10A, 12A) encompass or correspond to soldering areas (10, 12), and the method further comprises an additional step of soldering at least one connector to at least part of an extra thickness area (10A, 12A), particularly on the soldering areas (10, 12).

13. The method according to the preceding claim, wherein the connector is metallic, in particular made of steel containing chrome, and the soldering is carried out using a lead-free, tin-based, silver-based and copper-based soldering alloy.

14. The method according to one of claims 7 to 13, wherein the glazing obtained is a rear window of a motor vehicle, a side glazing of a motor vehicle or a windscreen of a motor vehicle, with the electroconductive patterns notably being antennas (6), bus bars (8), alarm wires and / or heating wires (4), and the, or each, extra thickness area (10A, 12A) encompassing or being a soldering area for connecting an antenna (10A) and / or a heating network (12A) and / or an alarm network.

15. A glazing (1) obtained by the method of one of claims 7 to 14, said glazing comprising a glass sheet (2) covered with electroconductive patterns (4, 6, 8, 10) on one of its faces and having in at least one area (10A, 12A), the so-called extra thickness area, a greater thickness than in the other areas.