System and method for coating a glass substrate

Abstract

System and Method for Coating a Glass Substrate The invention relates to a system (100) for coating a glass substrate (200) by sputtering, said system comprising a series of sputtering chambers and a support (140) configured to move the glass substrate through the chambers, at least one of the chambers (120) being coupled to an alternating current power supply (150) connected to two electrodes (160, 170) by means of two respective power lines (161, 171). Furthermore, the system comprises at least one element, referred to as a "filtering element" (300), made of at least one material capable of filtering electrical currents in at least one determined frequency range and arranged so as to be traversed at least once by at least one of said two lines. Figure for the abstract: Fig. 2

Description

Title of the invention: System and method for coating a glass substrate Prior art

[0001] The present application belongs to the general field of the deposition of thin layers on glass substrates, in particular glass substrates for construction (windows, facades, partitions) or even for transport. It relates more particularly to a system for coating a glass substrate by cathodic sputtering, a coating method implemented by such a system as well as a glass substrate obtained by this method. The invention finds applications in particular in the field of construction (windows, facades, partitions, etc.) as well as in the field of transport (automobile, etc.).

[0002] In a known manner, glass substrates can be coated with a set (stack) of thin layers, also called thin films. Such thin layers are used in particular to vary the optical properties of the coated substrates, in other words their capacity to transmit visible light more or less easily while minimizing the transmission of other wavelengths of radiation, in particular radiation in the infrared spectrum. In this way, it is possible to minimize heat transfer by radiation without impairing the transmission of visible light.

[0003] For example, coatings having high visible transmission and low emissivity characteristics typically include one or more infrared reflective layers and two or more anti-reflective transparent dielectric layers. The infrared reflective layers, which typically include conductive metals such as silver, gold, or copper, reduce the transmission of radiant heat through the coating. The transparent dielectric layers, on the other hand, are primarily used to reduce visible reflection, but also to provide mechanical and chemical protection to the infrared reflective layers, as well as to control other optical properties of the coating, such as color.Commonly used transparent dielectrics include oxides of zinc, silicon, tin, and titanium, as well as nitrides of silicon, chromium, zirconium, and titanium.

[0004] The deposition of a thin layer on a glass substrate is conventionally carried out using the cathode sputtering technique, also called magnetron sputtering technique. This technique is implemented within a low-pressure chamber whose atmosphere is either composed exclusively of an inert gas (eg argon), or contains a mixture of inert gas with one or more reactive gases (eg oxygen, nitrogen, etc.). The chamber is notably coupled to a power supply connected to electrodes. This configuration allows the formation of a plasma which remains confined by a magnetic field, so as to allow the ejection of atoms from a target integrated into the electrodes, with a view to their deposition on a surface of the glass substrate and thus form the thin layer. The term "sputtering" therefore makes it possible to characterize this ejection and deposition of atoms from a target.

[0005] In practice, to obtain multilayer coatings, production lines are used where a glass substrate passes through a series of sputtering chambers, each sputtering chamber being able to comprise one or more targets. In general, the principles underlying the implementation of the cathode sputtering technique for obtaining a multilayer coating, as well as the equipment necessary for this implementation, are well known and are therefore not described further here.

[0006] When conductive layers (metallic, ceramic) are present on the surface of the glass substrate, following deposition in a production line comprising sputtering chambers, and one or more of these chambers are coupled to alternating current power supplies, it is not uncommon to observe the appearance of defects in the form of cracks (known as "crazing defects" in English) on the surface of the glass substrate. [Fig. 1] schematically represents an example of a glass substrate 1 comprising cracks 2. As can be seen in [Fig. 1], these cracks 2 constitute visual defects in the form of a network of fine "lightning strike" type lines, which are all the more troublesome when they extend far from the edges of the glass substrate 1. A glass substrate 1 thus marked by cracks 2 becomes unusable.

[0007] Various attempts have been made to try to reduce the risk of such cracks appearing. For example, it has been considered to reduce the electrical power supplied by the power supplies of the sputtering chambers, or to grind the cracked edges of the glass substrate. However, these attempts cannot be considered as effective solutions. Indeed, the first (power reduction) implies in particular a reduction in production capacity. The second (grinding) involves carrying out additional operations during the production process, which complicates it and increases its cost. Furthermore, and more fundamentally, neither of these two solutions makes it possible to completely eliminate the appearance of cracks.

[0008] A more recent attempt, notably described in document WO2018026598, is based on a hypothesis according to which the origin of the cracks comes from a alternating current coupling in the stacked layers. It is then proposed to connect a suitable device between the power lines connecting said electrodes to their power supply and to the ground. Such a device in question notably comprises diodes capable of grounding an electrode when the voltage applied to the latter is positive (with respect to the ground).

[0009] This latter solution nevertheless remains deficient in that it only makes it possible to reduce the appearance of cracks in very few configurations of a production line. In particular, it has been observed that if a production line comprises, for example, two spray chambers both powered by an alternating current and sufficiently close to each other (e.g. their respective electrodes are separated by a distance less than that of the glass substrate in the direction of movement through the chambers), the appearance of cracks is, on the contrary, amplified.

[0010] Statement of the invention

[0011] The present invention aims to overcome all or part of the drawbacks of the prior art, in particular those set out above, by proposing a solution which makes it possible to reduce, more effectively than the solutions of the state of the art, the appearance of cracks in stacks of thin layers of glass substrates, such stacks comprising one or more conductive thin layers. In particular, the solution proposed by the invention advantageously makes it possible to eliminate the appearance of cracks in a particularly simple and inexpensive manner.

[0012] To this end, and according to a first aspect, the invention relates to a system for coating a glass substrate by cathode sputtering, said system comprising a series of sputtering chambers as well as a support configured to move the glass substrate through the chambers, at least one of the chambers being coupled to an alternating current power supply connected to two electrodes by means of two respective electrical lines. Furthermore, the system comprises at least one element, called a "filtering element", made of at least one material capable of filtering electrical currents in at least one determined frequency range and arranged so as to be crossed at least once by at least one of said two lines.

[0013] As mentioned above, various attempts have been made to try to reduce the risk of cracks appearing on the surface of a glass substrate coating. None of these prior art attempts can truly be considered effective, and this is why the inventor has sought to approach the problem of cracks appearing from a new angle.

[0014] More particularly, the inventor has put forward the hypothesis that the appearance of cracks results from the existence of an electrical deviation in the path that the electric current is theoretically supposed to follow at the level of the sputtering chambers when these are operating under nominal conditions. This is in particular a deviation which causes the electric current to circulate on the surface of the glass substrate.

[0015] It should be noted that the inventor also noticed that the frequency of appearance of cracks in a spray chamber coupled to an alternating current power supply was correlated with the presence of positive voltage peaks (relative to an electrical ground reference potential, for example the earth) measured at each electrode.

[0016] Ultimately, to eliminate the appearance of cracks on the surface of the glass substrate, the inventor sought a way to prevent current deviations from the expected electrical path, in particular by eliminating these positive voltage peaks, and arrived at a solution consisting of the implementation of said at least one filtering element. Excellent results were obtained, as described in more detail later.

[0017] In particular embodiments, the coating system may further comprise one or more of the following features, taken individually or in any technically possible combination.

[0018] In particular embodiments, said system comprises a plurality of filtering elements, each of said filtering elements being arranged so as to be crossed at least once by at least one of said two lines.

[0019] In particular embodiments, at least one filtering element is crossed at least once by the two lines.

[0020] In particular embodiments, at least one filtering element is crossed at least once by only one of said two lines.

[0021] In particular embodiments, at least one of said two lines passes a plurality of times through each of the filtering elements among a set of one or more filtering elements.

[0022] In particular embodiments, at least one of said two lines crosses several filtering elements a plurality of times, making, during a crossing, a single loop around said filtering elements.

[0023] In particular embodiments, at least one filtering element comprises two through holes and is arranged so that at least one of said two lines passes through it via one of said two through holes in a first direction and via the other of said two through holes in a second direction distinct from the first direction.

[0024] In particular embodiments, at least one of the filtering elements has a roughly toric shape.

[0025] In particular embodiments, at least one of the filtering elements is positioned in the vicinity of the power supply or in the vicinity of at least one electrode.

[0026] In particular embodiments, at least one filtering element is crossed at least once by a shielded or unshielded part of at least one of said two lines.

[0027] In particular embodiments, at least one filtering element comprises clipping means configured to cooperate with each other, so as to maintain said at least one filtering element in a fixed position around at least one of said two lines.

[0028] In particular embodiments, at least one filtering element is made of ferrite.

[0029] In particular embodiments, the ferrite comprises Nickel and Zinc, or comprises Manganese and Zinc, or is configured such that the material of said at least one element is a nanomaterial.

[0030] In particular embodiments, said at least one material is capable of filtering electric currents of frequencies greater than 1 MHz, or greater than 100 kHz, or greater than 10 kHz.

[0031] In particular embodiments, said system further comprises cooling means configured to maintain the temperature of said at least one filtering element below a determined threshold.

[0032] In particular embodiments, said cooling means comprise a fan and / or a fluid cooling circuit and / or a heat sink.

[0033] According to a second aspect, the invention relates to a method for coating a glass substrate by cathodic sputtering, said method being implemented by a coating system according to the invention.

[0034] According to a third aspect, the invention relates to a glass substrate obtained from the coating process according to the invention.

[0035] Brief description of the drawings

[0036] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate an exemplary embodiment thereof without any limiting character. In the figures:

[0037] [Fig-1] [Fig.l] schematically represents an example of a glass substrate containing cracks;

[0038] [Fig.2] [Fig.2] schematically represents a particular embodiment of a coating system according to the invention;

[0039] [Fig.3] [Fig.3] schematically represents an example of a nominal (i.e. non-deviated) electrical path followed by the electric current in a spray chamber equipping the coating system of [Fig.2], as well as a deviation of the nominal electrical path;

[0040] [Fig.4] [Fig.4] is a graph comprising a curve representing an example of the temporal evolution of the voltage (referenced with respect to the ground) at an electrode arranged in a spray chamber of the coating system of [Fig.2];

[0041] [Fig.5] [Fig.5] a table listing examples of filter elements in the form of toroids made of ferrite, these filter elements being intended to be used in the coating system of [Fig.2];

[0042] [Fig.6] [Fig.6] is a graph comprising two curves each representing the time evolution of the voltage (referenced with respect to the ground) at the same electrode arranged in a spray chamber of the coating system of [Fig.2], respectively when no filter element is used and when a filter element is used;

[0043] [Fig.7] [Fig.7] schematically represents a particular configuration of a filtering element and electrical lines of the coating system;

[0044] [Fig.8] [Fig.8] schematically represents another particular configuration of a filtering element and electrical lines of the coating system;

[0045] [Fig.9] [Fig.9] schematically represents yet another particular configuration of filtering elements and electrical lines of the coating system;

[0046] [Fig. 10] [Fig. 10] schematically represents yet another particular configuration of filtering elements and electrical lines of the coating system;

[0047] [Fig. 11] [Fig. 11] schematically represents yet another particular configuration of filtering elements and electrical lines of the coating system;

[0048] [Fig. 12] [Fig. 12] schematically represents yet another particular configuration of a filtering element and electrical lines of the coating system;

[0049] [Fig. 13] [Fig. 13] represents, in the form of a flowchart, steps of a method for coating a glass substrate according to the invention.

[0050]

[0051] Description of embodiments

[0052] [Fig.2] schematically represents a particular embodiment of a coating system 100 according to the invention.

[0053] The coating system 100 comprises means configured to carry out the coating (i.e. the deposition of thin layers) of a glass substrate 200 by spraying. cathode.

[0054] In the present embodiment, the glass substrate 200 is made of mineral glass. Mineral glass here designates, for example, soda-lime glass, aluminosilicate glass, or borosilicate glass. However, nothing precludes considering a glass substrate 200 made of organic glass, for example, stretched polymethyl methacrylate (stretched PMMA), unstretched polymethyl methacrylate, polycarbonate (PC), polyethylene terephthalate (PET) or polyurethane (PU).

[0055] As illustrated by [Fig. 2], the coating system 100 comprises a series of spray chambers arranged along a production line. More particularly, and for reasons intended solely to simplify the description of the invention, [Fig. 2] forms a close-up view of the coating system 100, so as to show only three contiguous plasma spray chambers 110, 120, 130. It is nevertheless understood that, in general, no limitation is attached to the number of spray chambers that can be envisaged.

[0056] In order to allow movement of the glass substrate 200 through the chambers 110, 120, 130 (the direction of movement being symbolized by an arrow referenced “F” in [Fig.2]), the coating system 100 comprises a movement support 140, such as transport rollers. The movement of the glass substrate 200 is notably carried out in such a way that the chambers 110, 120, 130 can deposit thin layers on the surface of said glass substrate 200 when it passes through them.

[0057] In the embodiment described here with reference to [Fig. 2], the glass substrate 200 is dimensioned so as to pass through the three chambers 110, 120, 130 at a time, so that three different thin layers are deposited at the same time and thus form a multilayer coating (i.e. a stack of thin layers). However, nothing precludes considering, in addition or as an alternative, the deposition of one or more layers in different locations on the surface of the glass substrate 200, so that these layers do not overlap.

[0058] As mentioned previously, the appearance of cracks such as those represented by [Fig. 1] is likely to occur when the glass substrate 200 is covered by at least one thin conductive layer (metallic, ceramic). Also, it is now considered in a non-limiting manner that when the glass substrate 200 arrives in the chamber 120 located between the two other chambers 110, 130, it already comprises at least one such conductive layer on the surface. For example, a conductive layer may be deposited by the sputtering chamber 110 located upstream of the sputtering chamber 120, or even by another sputtering chamber (not shown in the figures) located upstream of the chamber 110, or even have been deposited prior to the implementation of the invention.

[0059] It is nevertheless understood that such provisions are in no way limiting of the invention. In particular, it can be envisaged that the chamber 120 is the first of the chambers of the coating system 100 configured to deposit a conductive layer on the glass substrate 200.

[0060] For the remainder of the description, we will now detail the configuration of the coating system 100 with respect to the spray chamber 120 alone. It nevertheless remains that the configuration thus described can also be applied to any of the other chambers belonging to the coating system 100.

[0061] As illustrated by [Fig. 2], the spray chamber 120 is coupled to an alternating current power supply 150. This is for example an “AC” type power source (acronym for the English expression “Alternating Current”), for example more particularly a medium frequency power source of the MF / AC type (“MF” being the acronym for the English expression “Mid Frequency”), or a bipolar type power source.

[0062] The power supply 150 is connected to two electrodes 160, 170 positioned within the spray chamber 120. The connection between the power supply 150 and the two electrodes 160, 170 is made by means of two respective electrical lines 161, 171. Each electrical line 161, 171 may comprise a single electrical cable or several electrical cables connected together at their ends. In a manner known per se, the role played by each of the two electrodes 160, 170 depends on the type of the power supply 150. Thus, the electrodes 160, 170 can alternately play the role of cathode and anode (polarization variation at each half-period of the current), or each retain a role of cathode (to perform the spraying function) or anode (to perform the current continuity function).Generally speaking, the configuration of the roles played by each of the electrodes 160, 170 is well known to those skilled in the art, and is therefore not detailed further here.

[0063] No limitation is attached to the shape and arrangement taken by the power supply 150, the electrodes 160, 170 and the power lines 161, 171. For example, the electrodes 160, 170 can be cylindrical and rotatable or even flat, and be arranged at a determined distance from the walls of the spray chamber 120.

[0064] Furthermore, in the embodiment illustrated by [Fig. 2], the power supply 150 and the electrodes 160, 170 are not connected to ground. However, nothing precludes considering that these elements are grounded, directly or indirectly (i.e. grounded, via an element of the coating system 100, this ground itself being connected to ground). The spray chamber 120, for its part, is grounded by means of a connection 121. It should be noted that when the spray chambers 110, 120, 130 are electrically coupled together, the single connection 121 makes it possible to ground them all.

[0065] The displacement support 140 can be electrically isolated from the other elements of the system 100 (i.e. floating potential) or else be grounded.

[0066] Conventionally, the coating system 100 also comprises other elements / devices / components used in the state of the art to carry out the deposition of thin layers within the sputtering chambers, such as in particular sputtering targets and magnets integrated into the electrodes 160, 170. These elements / devices / components being well known, they are not shown in [Fig. 2] nor even described further here.

[0067] In the embodiment of [Fig.2], the coating system 100 also comprises an element, called “filtering element 300”, capable of filtering electric currents in a determined frequency range and arranged so as to be crossed once by the two electric lines 161, 171.

[0068] This filtering element 300 defines a variant of the solution found by the inventor to avoid the appearance of cracks. Before describing said filtering element 300 in detail, the inventive reasoning leading to its introduction into the coating system 100 will first be explained.

[0069] Thus, as mentioned above, various attempts have been made to try to reduce the risk of cracks appearing on the surface of a glass substrate coating. None of these prior art attempts can truly be considered effective, and this is why the inventor has sought to approach the problem of cracks appearing from a new angle. More particularly, the inventor has put forward the hypothesis that the appearance of cracks results from the existence of an electrical deviation in the path that the electric current is theoretically supposed to follow at the level of the sputtering chambers when these are operating under nominal conditions.

[0070] [Fig. 3] schematically represents an example of a nominal (i.e. non-deviated) electrical path followed by the electric current in the spray chamber 120 equipping the coating system 100.

[0071] This nominal path is represented by arrows filled in black, which start from the electrical power supply 150, follow the electrical line 161 to arrive at the electrode 160. This nominal path continues within the plasma (not shown) created in the sputtering chamber 120, that is to say between the glass substrate 200 and the electrodes 160, 170, then goes back up towards the electrical power supply 150 via the electrode 170 and the electrical line 171.

[0072] Also shown in [Fig. 3] is an example of a diverted electrical path that may be taken by the current when the filtering element 300 is not present, in other words when the coating system is devoid of a filtering element, as is the case in the solutions proposed until now by the state of the art. technique. This diverted path initially follows a route identical to that of the nominal path between the power supply 150 and the plasma. However, in this example, a deviation (represented by dotted arrows) occurs which prevents the electric current from rising towards the electrode 170 and forces the latter to circulate on the surface of the glass substrate 200, which generates cracks. This deviation originates from the fact that the electric current is discharged towards a part 400 connected to the ground and follows a return path towards the power supply 150. This return path can be any path allowing it to return to the power supply 150, such as for example passing through the ground (chassis, electrical cable shields) and the power line 171.

[0073] It is therefore understood that the deviation takes place here due to the presence of the part 400 making it possible for certain frequencies of the electric current to pass through. No limitation is attached to the nature of said part 400, which may or may not be grounded as in the example of [Fig.3]. It may be an element / device / component of the coating system 100 itself, such as for example a wall of a spray chamber.

[0074] It should be noted that the inventor also noticed that the frequency of appearance of cracks in a spray chamber coupled to an alternating current power supply was correlated with the presence of positive voltage peaks measured at each electrode.

[0075] [Fig. 4] is a graph comprising a curve C representing an example of the temporal evolution (abscissa “t” in microseconds) of the voltage (ordinates “V” in volts) at any one of the electrodes 160, 170. As can be observed, positive voltage peaks PI, P2 appear during changes in voltage polarity. However, it is precisely when these peaks PI, P2 occur that, on the one hand, the electrical path is assumed (by the inventor) to be deviated from its normal path, but also that the inventor has observed that cracks have appeared.

[0076] Ultimately, to eliminate the appearance of cracks on the surface of the glass substrate 200, the inventor sought a means of preventing current deviations from the expected electrical path, more particularly by eliminating these positive voltage peaks, and arrived at a solution consisting of the implementation of the filtering element 300.

[0077] Thus, returning to [Fig. 2], and as already mentioned, the filtering element 300 is configured to filter (absorb) electric currents in a determined frequency range and arranged so as to be crossed right through by the two electric lines 161, 171. Carrying out this filtering in this position configuration advantageously makes it possible to avoid current deviations by relative to the expected electrical path.

[0078] More particularly, in the embodiment described here, the filtering element 300 has a substantially toroidal shape. The two electrical lines 161, 171 therefore pass through the filtering element 300 from one side to the other, passing through a hole defining said toroidal sensitive shape. In other words, in a cross-section to the electrical lines 161, 171, the filtering element 300 has a substantially annular shape within which said lines 161, 171 pass.

[0079] However, considering a substantially toroidal shape for the filtering element 300 only constitutes a variant implementation of the invention, and nothing excludes the possibility of considering other shapes. Generally speaking, no limitation is attached to the shape of the filtering element 300 provided that the latter comprises at least one hole allowing the electrical lines 161, 171 to pass right through it.

[0080] Furthermore, and as illustrated by [Fig. 2], the filtering element 300 is positioned substantially halfway between the electrodes 160, 170 and the electrical power supply 150. Such positioning is however not limiting of the invention, and nothing excludes the possibility of considering other alternatives, such as for example a positioning of the filtering element 300 in the vicinity of the electrical power supply 150 or in the vicinity of the electrodes 160, 170.

[0081] Conventionally, the cable or cables forming an electrical line 161, 171 may be shielded in whole or in part (i.e. each comprise a shielding sheath). Also, and according to a preferred embodiment, the filtering element 300 is crossed by a part of said two electrical lines 161, 171 that is not shielded, i.e. a part at which the cable or cables forming a line are not shielded. As the cable or cables of a line are a priori initially shielded (i.e. before the implementation of the filtering element 300, at the time of their manufacture), it is understood that this shielding should be removed locally at the location where the filtering element 300 is intended to be positioned.

[0082] It has been found that considering positioning at a portion without shielding makes it possible to improve the effectiveness of the filtering element 300 with regard to crack suppression. That being said, nothing precludes considering that the filtering element 300 is crossed by a shielded portion of said two electrical lines 161, 171, excellent results in terms of crack suppression having also been obtained in this configuration.

[0083] As regards maintaining the filtering element 300 in position, here too, no limitation applies within the meaning of the present invention. Thus, by way of non-limiting example, the filtering element 300 may comprise clipping means (not shown) configured to cooperate with each other, so as to maintain said filtering element 300 in a fixed position around the two lines electrical 161, 171. Said clipping means may for example be integrated into a housing inside which is placed a material suitable for performing the filtering function, as now described in more detail.

[0084] In the present embodiment, the filtering element 300 is made of ferrite.

[0085] According to a more particular example, the ferrite composing the filtering element 300 comprises Nickel and Zinc (NiZn Ferrite).

[0086] According to another example, the ferrite composing the filtering element 300 comprises Manganese and Zinc (Ferrite MnZn).

[0087] According to yet another example, the ferrite composing the filtering element 300 is configured so that the material of said filtering element 300 is a nanomaterial.

[0088] It should be noted that considering ferrite as the basic material for producing the filtering element 300 only constitutes a variant implementation of the invention, other materials being able to be envisaged such as for example nanomaterial alloys based on iron, silicon, boron, niobium and copper.

[0089] The use of such materials is particularly well suited to filtering frequencies in a given frequency range. Generally speaking, a person skilled in the art knows how to choose (for example from catalogs of specialized merchants) one or more materials capable of selectively filtering electrical frequencies, and thus allowing the production of a filtering element 300.

[0090] Examples of frequency ranges are for example the following: - frequencies above 10 kHz, for example between 10 kHz and 200 MHz, or - frequencies above 100 kHz, for example between 100 kHz and 200 MHz, more particularly between 100 kHz and 50 MHz or - frequencies above 1 MHz, for example between 1 MHz and 200 MHz, more particularly 50 MHz and 200 MHz.

[0091] More specific examples of toroids made of ferrite and from which excellent crack suppression results have been obtained are listed in a non-limiting manner in the table of [Fig. 5]. In this table are indicated successively: the specific material used, the filtering frequency range, the external diameter (“OD”) of the toroid in millimeters, the internal diameter (“ID”) of the toroid in millimeters, and the height (“H”) of the toroid in millimeters.

[0092] [Fig. 6] is a graph comprising two curves C1, C2 each representing the temporal evolution of the voltage at the same electrode among any one of the electrodes 160, 170. Curve C1 (respectively curve C2) represents in a uniform solid line (respectively in a solid line with squares) the temporal evolution of the voltage when no filtering element is used. (respectively when the filter element 300 is used). More particularly, these two curves Cl, C2 were obtained during a test campaign carried out according to the following provisions: - two rotating cathodes 160, 170, - power lines 161, 171 approximately 15 meters long, - 150 bipolar type power supply operating at a frequency of 40 kHz for a power of 30 kW, - atmosphere formed from a mixture of argon and oxygen under a pressure of 3 bars in the spray chamber 120, - filter element 300 identical to that present in the fourth line of the table in [Fig.5].

[0093] As can be seen in [Fig.6], curve C1 comprises three positive voltage peaks P1, P2, P3. Furthermore, and advantageously, the use of the filtering element 300 makes it possible to eliminate the positive voltage peaks. Correlatively, it was found that no cracks appeared on the glass substrate obtained at the output of the production line. It is deduced from this, in accordance with the hypotheses formulated by the inventor, that the filtering element 300 made it possible to prevent any current deviation via the conductive surface of the glass substrate 200.

[0094] The coating system 100 has been described so far considering that only one filtering element 300 was used. What is more, this filtering element 300 was arranged so as to be crossed only once by the two electrical lines 161, 171 at the same time. Such arrangements are however not limiting of the invention, and multiple other embodiments can still be envisaged, as is now detailed.

[0095] [Fig. 7] schematically represents another embodiment of the coating system 100. More particularly, [Fig. 7] corresponds to a close-up view illustrating a configuration in which each electrical line 161, 171 passes twice through the filtering element 300 (these two crossings comprise a direct crossing of the filtering element 300 and a crossing made by winding the electrical line on itself and around the structure of the filtering element 300, as illustrated by [Fig. 7]). By making these two crossings of the filtering element 300, it has been found that this makes it possible to improve the efficiency of the coating system 100 with respect to the problem of crack suppression, and also makes it possible to reduce heating of the filtering element 300.

[0096] Furthermore, considering these two crossings of the filtering element 300 constitutes only a variant implementation of the invention. In general, no limitation is attached to the number of crossings that it is possible to envisage for each of the electrical lines 161, 171. [Fig. 8] illustrates in a schematically an exemplary embodiment in which each electrical line 161, 171 passes through the filtering element 300 three times (these three crossings comprise a direct crossing of the filtering element 300 and two crossings made by two windings of the electrical line on itself and around the structure of the filtering element 300, as illustrated by [Fig.8]).

[0097] [Fig. 9] schematically represents yet another embodiment of the coating system 100. More particularly, [Fig. 9] corresponds to a close-up view illustrating a configuration in which four filtering elements 301, 302, 303, 304 are used. Said four filtering elements 301, 302, 303, 304 are all arranged so as to be crossed only once by the two electrical lines 161, 171 at the same time.

[0098] Considering four filtering elements 301, 302, 303, 304 of course only corresponds to a variant implementation of the invention. Generally speaking, no limitation is attached to the number of filtering elements that can be used.

[0099] [Fig. 10] schematically represents yet another embodiment of the coating system 100. More particularly, [Fig. 10] corresponds to a close-up view illustrating a configuration in which four filtering elements 301, 302, 303, 304 are used and each electrical line 161, 171 passes twice through each of said four filtering elements 301, 302, 303, 304, each making a single loop around them.

[0100] It is of course understood that, here again, the fact of considering four filtering elements is not limiting of the invention. Furthermore, nothing excludes the possibility that the configuration of [Fig. 10] is ultimately achieved only by one of the electrical lines 161, 171, the other remaining line being able for example to pass through the filtering elements only once, or even to pass through one or more of them one or more times.

[0101] [Fig. 11] schematically represents yet another embodiment of the coating system 100. More particularly, [Fig. 11] corresponds to a close-up view illustrating a configuration in which two filtering elements 301, 302 are used, each of said filtering elements 301, 302 being crossed only once by only one of said two electrical lines 161, 171.

[0102] The invention has also been described up to now by considering a filtering element comprising a single through-hole (e.g. substantially toroidal shape). However, such arrangements are not limiting of the invention, and nothing excludes having at least one filtering element with several through-holes through which one or more electrical lines can pass. For example, and as illustrated by [Fig. 12] in no way limiting, the filtering element 300 may comprise two through-holes T1, T2 and be arranged so that the two lines 161, 171 passes through it via the through hole T1 in a first direction and via the other through hole T2 in a second direction distinct from the first direction. It is of course understood here again that a similar configuration can be envisaged in the case where only one of said two lines 161, 171 passes through the holes T1, T2.

[0103] Generally speaking, all the embodiments described above, in particular those described with reference to FIGS. 2, 7, 8, 9, 10 and 11, can be envisaged for the coating system in any technically operative combination. In particular, it is possible to have one or more filtering elements crossed by the two electrical lines of the electrodes and / or one or more filtering elements crossed by only one of said electrical lines.

[0104] To the extent that the filtering element(s) used can absorb electrical currents according to one or more frequency ranges, it is understood that they are likely to undergo heating. This heating can in particular be reduced when a filtering element is crossed several times by an electrical line. Alternatively, or in addition, the coating system 100 may further comprise cooling means (not illustrated) configured to maintain the temperature of the filtering element(s) below a determined threshold.

[0105] Said temperature threshold is for example set at 80°C, preferably less than 50°C.

[0106] No limitation is attached to the nature or configuration of the cooling means that can be used. For example, the cooling means may comprise a fan and / or a cooling fluid circuit and / or a heat sink. When a fluid circuit is considered, it is advantageous to envisage one or more filtering elements bearing a coating capable of protecting them from the risk of corrosion.

[0107] Finally, according to yet another aspect, the invention also relates to a method for coating the substrate 200 by cathode sputtering. This coating method is implemented by the coating system 100, and may in particular comprise, as illustrated in a non-limiting manner by [Fig. 13], the following steps: - movement E10 of the glass substrate 200 through the spraying chambers 110, 120, 130. This movement step E10 is implemented by the transport support 140, - E20 deposition of thin layers in each of the sputtering chambers 110, 120, 130.

Claims

Claims

1. System (100) for coating a glass substrate (200) by cathodic sputtering, said system comprising a series of sputtering chambers and a support (140) configured to move the glass substrate through the chambers, at least one of the chambers (120) being coupled to an alternating current power supply (150) connected to two electrodes (160, 170) by means of two respective electrical lines (161, 171), the system being characterized in that it comprises at least one element, called a "filtering element" (300), made of at least one material capable of filtering electric currents in at least one determined frequency range and arranged so as to be crossed at least once by at least one of said two lines.

2. System (100) according to claim 1, said system comprising a plurality of filtering elements, each of said filtering elements being arranged so as to be crossed at least once by at least one of said two lines.

3. System (100) according to any one of claims 1 to 2, in which at least one filtering element is crossed at least once by the two lines.

4. System (100) according to any one of claims 1 to 3, in which at least one filter element is crossed at least once by only one of said two lines.

5. The system (100) of any one of claims 1 to 4, wherein at least one of said two lines passes a plurality of times through each of a set of one or more filter elements.

6. System (100) according to any one of claims 1 to 4 and according to claim 2, in which at least one of said two lines crosses a plurality of times several filter elements by making, during a crossing, a single loop around said filter elements.

7. System (100) according to any one of claims 1 to 4, in which at least one filtering element comprises two through holes and is arranged so that at least one of said two lines passes through it via one of said two through holes in a first direction and via the other of said two through holes in a second direction distinct from the first direction.

8. A system (100) according to any one of claims 1 to 7, wherein at least one of the filtering elements has a substantially toroidal shape.

9. The system (100) of any one of claims 1 to 8, wherein at least one of the filtering elements is positioned adjacent to the power supply (150) or adjacent to at least one electrode (160, 170).

10. System (100) according to any one of claims 1 to 9, in which at least one filtering element is crossed at least once by a shielded or unshielded part of at least one of said two lines.

11. System (100) according to any one of claims 1 to 10, in which at least one filtering element comprises clipping means configured to cooperate with each other, so as to maintain said at least one filtering element in a fixed position around at least one of said two lines.

12. System (100) according to any one of claims 1 to 11, in which at least one filtering element is made of ferrite.

13. The system (100) of claim 12, wherein the ferrite comprises Nickel and Zinc, or comprises Manganese and Zinc, or is configured such that the material of said at least one element is a nanomaterial.

14. System (100) according to any one of claims 1 to 13, wherein said at least one material is capable of filtering electric currents of frequencies greater than 10 kHz, or greater than 100 kHz, or greater than 1 MHz.

15. System (100) according to any one of claims 1 to 14, said system further comprising cooling means configured to maintain the temperature of said at least one filtering element below a determined threshold.

16. System (100) according to claim 15, wherein said cooling means comprise a fan and / or a cooling fluid circuit and / or a heat sink.

17. A method of coating a glass substrate by cathodic sputtering, said method being carried out by a coating system (100) according to any one of claims 1 to 16.

Images