Abstract
A method for processing a substrate is presented. The substrate includes an electrically conductive coating, and at least one isolating line that runs between first and second subregions of the electrically conductive coating. According to one aspect, the isolating line includes at least one defect with a proportion of less than 10% of the total surface area of the isolating line. First and second electric contacts are respectively connected to the first and second subregion. A voltage U.sub.n is applied between the first and second electric contacts, and a measurement is taken to detect whether an electric current is flowing between the first and the second subregions. If a current is flowing, application of the voltage and measurement of the current are repeated with a voltage greater than or equal to U.sub.n, until a current can no longer be measured.
Claims
1.-14. (canceled)
15. A method for processing a substrate having an electrically conductive coating and at least one isolating line, the method comprising: a) providing a substrate, the substrate comprising: a1) an electrically conductive coating on at least one surface of the substrate; a2) at least one isolating line in the electrically conductive coating; a3) at least one first subregion and one second subregion of the electrically conductive coating between which the isolating line runs; a4) optionally, at least one defect of the isolating line in a region of the isolating line where a local sheet resistance is lower than a sheet resistance of the isolating line outside the defect; b) electrically conductingly connecting a first electric contact to the first subregion and a second electric contact to the second subregion of the electrically conductive coating; c) applying a voltage U.sub.n between the first electric contact and the second electric contact; d) measuring, using the first electric contact and the second electric contact, a flow of an electric current between the first subregion and the second subregion; e) if an electric current is flowing between the first subregion and the second subregion, then repeating steps c) and d) with a voltage greater than or equal to U.sub.n, until, in step d), a current flow can no longer be measured between the first subregion and the second subregion, wherein an areal proportion of the defect to a total surface area of the isolating line is less than 10%.
16. The method according to claim 15, wherein the voltage greater than or equal to U.sub.n of step e), is a voltage U.sub.n+1, with U.sub.n+1>U.sub.n, that is increased iteratively with each repetition of the step e).
17. The method according to claim 15, wherein each of the voltages U.sub.n and U.sub.n+1 is less than 200 V.
18. The method according to claim 15, wherein each of the voltages U.sub.n and U.sub.n+1 is between 3 V and 50 V.
19. The method according to claim 17, wherein the voltage in step c) is applied for 1 second to 10 seconds.
20. The method according to claim 17, wherein the voltage in step c) is applied for 2 seconds to 6 seconds.
21. The method according to claim 15, wherein the first electric contact and the second electric contact directly contact the electrically conductive coating in the first subregion and the second subregion respectively.
22. The method according to claim 15, wherein: prior to step b), at least one busbar is electrically conductingly applied on the electrically conductive coating in at least one of the first subregion and the second subregion, and the at least one busbar produce no electric contact between the first subregion and the second subregion.
23. The method according to claim 22, wherein step b) further comprises contacting the first electric contact and the second electric contact to the at least one busbar.
24. The method according to claim 15, wherein after step e), the substrate is laminated, with interposition of a thermoplastic intermediate layer, to at least one second substrate to form a composite pane.
25. A substrate comprising an electrically conductive coating and at least one isolating line, wherein the at least one isolating line comprises at least one repaired defect obtained according to the method of claim 15.
26. The substrate according to claim 25, wherein the substrate comprises glass or plastics.
27. The substrate according to claim 26, wherein the glass comprises one or more of borosilicate glass and soda lime glass.
28. The substrate according to claim 26, wherein the plastics comprises one or more of polycarbonate, polymethylmethacrylate, polyethylene, and polyethylene terephthalate.
29. The substrate according to claim 25, wherein the electrically conductive coating contains at least one of: a) silver, and b) an electrically conductive oxide.
30. The substrate according to claim 25, wherein the substrate is laminated to a second substrate with interposition of a thermoplastic intermediate layer, to form a composite pane.
31. The substrate according to claim 30, wherein the substrate is laminated to form a windshield and the at least one isolating line runs along a center of the composite pane perpendicular to a roof edge of the windshield.
32. A method, comprising: processing a substrate having an electrically conductive coating and at least one isolating line according to the method of claim 15; and based on the processing, repairing the at least one isolating line in the electrically conductive coating, wherein the substrate with the electrically conductive coating is used in automobile glazing.
33. The method according to claim 32, wherein the automobile glazing comprises at least one of: a) a windshield, b) a side window, and c) a rear window.
Description
[0068] They depict:
[0069] FIGS. 1a and 1b a substrate having an electrically conductive coating, which is divided by an isolating line into two subregions, wherein the isolating line has a defect,
[0070] FIG. 2 the substrate of FIGS. 1a and 1b, wherein in each case a contact is placed on the first subregion and on the second subregion, between which a current flows,
[0071] FIGS. 3a and 3b the substrate of FIGS. 1a and 1 b after execution of the method according to the invention, laminated as a composite pane with a second substrate and a thermoplastic intermediate layer,
[0072] FIG. 4 another substrate after use of the method according to the invention, laminated as a composite pane with a second substrate and a thermoplastic intermediate layer,
[0073] FIG. 5 a detail of another substrate after use of the method according to the invention,
[0074] FIGS. 6, 7, and 8 a schematic enlarged representation in each case of a substrate before use of the method according to the invention (a) and after use of the method according to the invention (b),
[0075] FIG. 9 a flowchart of an embodiment of the method according to the invention.
[0076] FIGS. 1a and 1b depict a substrate (1) having an electrically conductive coating (2), which is divided by an isolating line (3) with a width of 100 m into a first subregion (2.1) and a second subregion (2.2), wherein the isolating line (3) has a defect (3.1). The isolating line (3) runs perpendicular to the roof edge (A) or to the engine edge (B). The basic shape of the substrate (1) corresponds to a windshield of a passenger car. Two busbars (5) in each case are applied in each of the subregions (2.1, 2.2). In each case one busbar (5) per subregion (2.1, 2.2) runs parallel to the roof edge (A) of the substrate (1), whereas one busbar per subregion (2.1, 2.2) is applied parallel to the engine edge (B) of the substrate (1). The busbars (5) extended each case only within one of the subregions (2.1, 2.2). Two heating fields switchable independently of one another are supposed to be produced by means of this arrangement of the busbars (5) and the isolating line (3). The substrate in FIGS. 1a and 1b is, however, not capable of functioning in this form since the isolating line (3) has a defect (3.1). FIG. 1b depicts an enlarged representation of the defect (3.1) of the isolating line (3). In the region of the defect (3.1), the first subregion (2.1) and the second subregion (2.2) of the coating (2) are electrically conductingly connected to one another. The defect (3.1) is caused by electrically conductive particles that establish an electrically conducting connection of the subregions (2.1, 2.2). The substrate (1) is made of soda lime glass with a thickness of 1.6 mm. The electrically conductive coating (2) includes three conductive silver layers with dielectric layers arranged therebetween. The electrically conductive coating (2) was deposited on the substrate (1) by magnetron sputtering. The isolating line (3) was introduced into the electrically conductive coating (2) by laser ablation. The busbars (5) are implemented as a printed conductive structure. For this, a silver-containing screenprinting paste was printed and fired. Since the subregions (2.1, 2.2) are electrically conductingly connected via the defect (3.1), independent heating of the subregions (2.1, 2.2) is not possible since a flow of current occurs via the defect (3.1). The substrate (1) is thus not commercially exploitable without remedying the defect (3.1).
[0077] FIG. 2 depicts the substrate of FIGS. 1a and 1 b, wherein in each case on one busbar (5) of each subregion (2.1, 2.2), an electric contact (4.1, 4.2) is electrically conductingly contacted. In the first subregion (2.1), the first electric contact (4.1) is placed on the busbar (5) situated adjacent the roof edge (A). Within this busbar (5), the first electric contact is positioned on the end of the busbar (5) adjacent the nearest side edge (E). The second electric contact (4.2) is mounted diagonally opposite the first electric contact (4.1) on a busbar (5) of the second subregion (2.2). The second electric contact (4.2) is placed in the second subregion (2.2) on the busbar (5) adjacent the engine edge (B). In this case, as well, the positioning is done on the end of the busbar (5) adjacent the nearest side edge (E). Upon application of a voltage between the electric contacts (4.1, 4.2), a current flows via the relevant busbar (5) and the coating (2) between the first electric contact (4.1) and the second electric contact (4.2). The flow of current between the subregions (2.1, 2.2) occurs exclusively via the defect (3.1), since this is the only electrically conducting connection of the subregions (2.1, 2.2). The defect (3.1) is thus the region of the substrate (1) with the highest current density. The region (C) through which the current flows is sketched in FIG. 2 as a hatched area. The performance of the method according to the invention is also possible with any positioning of the electric contacts (4.1, 4.2), as long as the two contacts (4.1, 4.2) are contacted in the different subregions (2.1, 2.2) such that upon application of a voltage, the flow of current occurs via the defect (3.1). A positioning according to FIG. 2 is advantageous if, in the previous production process, there is already a measurement station for resistance measurement and quality control that has correspondingly positioned contacts.
[0078] FIGS. 3a and 3b depict the substrate (1) of FIGS. 1a and 1b after execution of the method according to the invention laminated as a composite pane with a second substrate (6) and a thermoplastic intermediate layer (7). First, a first electric contact (4.1) and a second electric contact (4.2) were placed on the substrate (1) of FIGS. 1a and 1 b, wherein the arrangement corresponds to that depicted in FIG. 2. A voltage of 14 V was applied for 5 seconds between the first electric contact (4.1) and the second electric contact (4.2). The high current density in the region of the defect (3.1) results in very strong local heating in this region, by means of which a region with thermally decomposed coating is created, which runs between the ends of the isolating line (3) and thus completes the isolating line (3). In the region of the thus produced repaired defect (3.2), current no longer flows between the subregions (2.1, 2.2). The repaired defect (3.2) is recognizable as such with corresponding optical enlargement; however, is not discernible and is optically inconspicuous for the observer in everyday use of the pane. With regard to the heating behavior, the substrate (1) with a repaired defect (3.2) is indistinguishable from substrates whose isolating line never had a defect. The substrate (1) treated according to the method according to the invention is laminated according to FIGS. 3a and 3b via a thermoplastic intermediate layer (7) with a second substrate (6) to form a windshield, with FIG. 3a depicting a plan view and FIG. 3b depicts a cross-section of this arrangement along the section line D-D. The substrate (1) with a repaired defect (3.2) of the isolating line (3) is, in this case, the inner pane of the windshield, wherein, in the installed position of the windshield, the outer side (IV) of the substrate (1) is directed toward the vehicle interior and the electrically conductive coating (2) is applied on the inner side (III) of the substrate (1). The thermoplastic intermediate layer (7) lies on the electrically conductive coating (2). The thermoplastic intermediate layer (7) is made of a polyvinyl butyral film with a thickness of 0.76 mm. The inner side (II) of the second substrate (6) is situated on the opposite surface of the thermoplastic intermediate layer (7). The second substrate (6) is made of soda lime glass with a thickness of 2.1 mm. The second substrate (6) is the outer pane of the windshield, with the outer side (I) of the second substrate (6) pointing in the direction of the external environment in the installed position.
[0079] FIG. 4 depicts another substrate (1) after use of the method according to the invention, mounting of busbars (5), and lamination with a thermoplastic intermediate layer (7) and a second substrate (6). The structure as well as the process parameters used correspond substantially to those described in FIGS. 3a and 3b. In contrast thereto, a single busbar (5), which electrically conductingly connects the first subregion (2.1) and the second subregion (2.2) is situated adjacent the roof edge (A). Such a configuration of the busbars (5) and the isolating line is, for example, selected in the case of windshields that are to be operated with a voltage of 42 V or 48 V. In particular, electric vehicles have these high on-board voltages, compared to the customary on-board voltage of 14 V. A pane design according to FIGS. 3a and 3b is designed for such an on-board voltage of 14 V, whereas higher voltages would result in undesirably high heating output. The configuration according to FIG. 4 results in that the two subregions (2.1, 2.2) function as serially connected heating fields, which results in a reduction of the heating output to the desired level. The method according to the invention is used in the case of a busbar configuration according to FIG. 4 prior to the mounting of the busbars (5). This is necessary since, otherwise, part of the flow of current occurs via the busbar (5) adjacent the roof edge (A) busbar (5) and not via the defect. After repair of the defect, the busbars (5) are applied and the substrate (1) is laminated analogously to the arrangement depicted in FIGS. 3a and 3b, yielding the composite pane according to FIG. 4.
[0080] FIG. 5 depicts a detail of another substrate (1) after use of the method according to the invention. The substrate (1) corresponds substantially to that described in FIGS. 1a and 1b. Various mutually concentric isolating lines (3) with a width of 35 m are introduced into the coating, which lines divide the coating into subregions (2.1, 2.2, 2.3, 2.4, 2.5). The isolating line (3) running between the first subregion (2.1) and the second subregion (2.2) has a repaired defect (3.2). For repairing the defect, the method according to the invention was used, wherein the first electric contact was positioned at an arbitrary position within the first subregion (2.1) and the second electric contact was positioned at an arbitrary position within the second subregion (2.2), and a voltage of 10 V was applied for 3 seconds.
[0081] FIGS. 6, 7, and 8 depict, in each case, a schematic enlarged representation of a substrate (1) prior to use of the method according to the invention (a) and after use of the method according to the invention (b). The substrate (1) corresponded in all cases to that depicted in FIGS. 1a and 1 b. A voltage of 20 V was applied for 3 seconds between the electric contacts (4.1, 4.2) placed according to FIG. 2. A series of experiments was performed with 1000 substrates in which, prior to performance of the method according to the invention, 30% of the substrates had a defect (3.1) of the isolating line (3). After performance of the method according to the invention, the share of substrates having defects was successfully reduced to 0%. All defects (3.1) of the isolating line (3) were eliminated by using the method according to the invention. Some substrates (1) that previously had a defect (3.1) were randomly taken and examined before or after use of the method according to the invention. FIGS. 6, 7, and 8 depict an enlarged representation of the surroundings of the defect (3.1) before use of the method (see FIGS. 6a, 7a, and 8a) and after use of the method (see FIG. 6b, 7b, 8b). The isolating line (3) produced by laser ablation is represented as a hatched area in the coating (2). In this region, the coating (2) is removed. After use of the method according to the invention, the ends of the isolating line (3) adjacent the defect (3.1) are connected by a region with thermally decomposed coating within the coating (2). In the region of this thermally decomposed coating, conductive components are no longer present. Thus, flow of current no longer occurs via the resultant repaired defect (3.2).
[0082] FIG. 9 depicts a flowchart of an embodiment of the method according to the invention for producing the composite pane described in FIGS. 3a and 3b. The process steps depicted in FIG. 9 are as follows: [0083] I Depositing an electrically conductive coating (2) on the inner side (III) of a substrate (1) [0084] II Introducing the isolating line (3) in the electrically conductive coating (2) using laser ablation [0085] III Applying the busbars (5) using screen printing [0086] IV Contacting a first electric contact (4.1) with the first subregion (2.1) and contacting a second electric contact (4.2) with the second subregion (2.2) of the electrically conductive coating (2) [0087] V Applying a voltage U.sub.n between the first electric contact (4.1) and the second electric contact (4.2) [0088] VI Measuring whether an electric current is flowing between the first subregion (2.1) and the second subregion (2.2) [0089] VIIa If a current is flowing between the first subregion (2.1) and the second subregion (2.2): Repeating the steps V and VI with a voltage U.sub.n+1, where U.sub.n+1 is greater than U.sub.n [0090] VIIb If no current is flowing between the first subregion (2.1) and the second subregion (2.2): Continuing the method with step VIII [0091] VIII Placing a thermoplastic intermediate layer (7) on the electrically conductive coating (2) of the substrate (1) [0092] IX Placing a second substrate (6) on the thermoplastic intermediate layer (7), with the inner side (II) of the second substrate (6) facing in the direction of the thermoplastic intermediate layer (7) [0093] X Laminating the layer stack to form a composite pane
[0094] The order of the steps II and III is arbitrary. Step III can, alternatively, also be done between step VIIb and step VIII.
LIST OF REFERENCE CHARACTERS
[0095] (1) substrate [0096] (2) electrically conductive coating [0097] (2.1) first subregion of the electrically conductive coating [0098] (2.2) second subregion of the electrically conductive coating [0099] (2.n) n-th subregion of the electrically conductive coating, where n an integer >1 [0100] (3) isolating line [0101] (3.1) defect of the isolating line [0102] (3.2) repaired defect [0103] (4) electric contacts [0104] (4.1) first electric contact [0105] (4.2) second electric contact [0106] (5) busbar [0107] (6) second substrate [0108] (7) thermoplastic intermediate layer [0109] (A) roof edge [0110] (B) engine edge [0111] (C) region through which current is flowing [0112] D-D section line [0113] (E) side edges [0114] (I) outer side of the second substrate [0115] (II) inner side of the second substrate [0116] (III) inner side of the substrate [0117] (IV) outer side of the substrate
