Abstract
A laminated pane with an electrically controllable functional element switchable in segments, includes first and second panes joined to one another via an intermediate layer, and a functional element embedded in the intermediate layer. The functional element includes, flat atop one another in this order, a first carrier film, a first flat electrode, an active layer, a second flat electrode, and a second carrier film, the first flat electrode is divided into segments by at least one separating line, a group of first bus bars electrically conductively contacts the first flat electrode, at least one second bus bar electrically conductively contacts the second flat electrode. In the region of a separating line a recess is introduced in the first electrode, which recess surrounds a portion of the first electrode and electrically insulates the portion situated within the recess from the surface region of the first electrode situated outside the recess.
Claims
1. A laminated pane with an electrically controllable functional element which is switchable in segments, at least comprising a first pane, a second pane, which are joined to one another via an intermediate layer, and a functional element that is embedded in the intermediate layer, wherein the functional element comprises, flat atop one another in this order, at least a first carrier film, a first flat electrode, an active layer, a second flat electrode, and a second carrier film, the first flat electrode is divided into a plurality of segments by at least one separating line, a group of first bus bars electrically conductively contacts the first flat electrode, at least one second bus bar electrically conductively contacts the second flat electrode, and wherein in a region of the at least one separating line at least one recess is introduced in the first flat electrode, which at least one recess surrounds a portion of the first flat electrode and electrically insulates the portion of the first flat electrode situated within the at least one recess from a surface region of the first flat electrode situated outside the at least one recess.
2. The laminated pane according to claim 1, wherein the at least one recess is configured in the form of a through-hole or as a partial recess.
3. The laminated pane according to claim 1, wherein a distance between the at least one recess and the second bus bar is 0.2 mm to 20.0 mm.
4. The laminated pane according to claim 1, wherein the at least one recess is introduced in the region of the at least one separating line, which lies between two adjacent bus bars of the group of the first bus bars.
5. The laminated pane according to claim 1, wherein a diameter of the at least one recess is 0.5 mm to 5.0 mm.
6. The laminated pane according to claim 1, wherein the recesses are introduced by means of laser drilling at least into the first carrier film and the first flat electrode.
7. The laminated pane according to claim 1, wherein the functional element is a PDLC functional element.
8. The laminated pane according to claim 1, wherein the first bus bars and the second bus bars comprise an electrically conductive structure and have a thickness of 5 μm to 40 μm.
9. The laminated pane according to claim 1, wherein the first flat electrode and the second flat electrode contain at least a metal, a metal alloy, or a transparent conductive oxide, and have a thickness of 10 nm to 2 μm.
10. The laminated pane according to claim 1, wherein the intermediate layer has a first thermoplastic laminating film, which is arranged between the functional element and the first pane, and has a second thermoplastic laminating film, which is arranged between the functional element and the second pane.
11. The laminated pane according to claim 10, wherein the functional element is circumferentially surrounded by a thermoplastic frame film, which is arranged between the first thermoplastic laminating film and the second thermoplastic laminating film.
12. A method for producing a laminated pane according to claim 1, comprising: a) providing a functional element, b) attaching a group of first bus bars on the first flat electrode and attaching at least one second bus bar on the second flat electrode, c) introducing at least one separating line, which divides the first flat electrode into at least two segments, in the first flat electrode of the functional element, d) introducing at least one recess in the first flat electrode in the region of at least one separating line, e) placing at least one first thermoplastic laminating film on a first pane, the functional element is placed on the first thermoplastic laminating film, at least one second thermoplastic laminating film and a second pane are arranged atop one another in this order on the functional element, and f) joining the first pane and the second pane by lamination, wherein an intermediate layer with an embedded functional element is formed from the first thermoplastic laminating film and the second thermoplastic laminating film, wherein the at least one recess electrically insulates the region of the first flat electrode within the recess from the region of the first flat electrode outside the recess.
13. The method according to claim 12, wherein the recesses are introduced by laser drilling at least into the first carrier film and the first flat electrode.
14. The method according to claim 12 or 13, wherein the separating lines in the first flat electrode are produced by laser-induced degeneration, by focusing a laser beam through the first carrier film onto the first flat electrode.
15. A method comprising providing a laminated pane according to claim 1 as building glazing or vehicle glazing.
16. The laminated pane according to claim 3, wherein the distance between the at least one recess and the second bus bar is 0.2 mm to 10.0 mm.
17. The laminated pane according to claim 5, wherein the diameter of the at least one recess is 0.8 mm to 3.0 mm.
18. The laminated pane according to claim 8, wherein the electrically conductive structure contains silver.
19. The laminated pane according to claim 9, wherein the first flat electrode and the second flat electrode contain a transparent conductive oxide.
20. The method according to claim 15, wherein the vehicle glazing is a windshield or a roof panel of a motor vehicle.
Description
[0113] The invention is explained in detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and are not to scale. The drawings in no way restrict the invention. They depict:
[0114] FIG. 1a a plan view of an embodiment of a laminated pane according to the invention as a windshield,
[0115] FIG. 1b a cross-section through the windshield according to the invention of FIG. 1a along the section line CC′,
[0116] FIG. 2a the functional element 5 of the windshield of FIGS. 1a and 1b,
[0117] FIG. 2b a cross-section through the functional element 5 of FIG. 2a along the section line AA′,
[0118] FIG. 2c a cross-section through the functional element 5 of FIG. 2a along the section line BB′,
[0119] FIG. 3 a plan view of an embodiment of a laminated pane according to the invention as a roof panel,
[0120] FIG. 4a the functional element 5 of the roof panel of FIG. 3,
[0121] FIG. 4b a cross-section through the functional element 5 of FIG. 4a along the section line EE′,
[0122] FIG. 4c a cross-section through the functional element 5 of FIG. 4a along the section line FF′,
[0123] FIG. 5 an exemplary embodiment of the method according to the invention using a flowchart.
[0124] FIG. 1a depicts a plan view of a laminated pane according to the invention, which is implemented as a windshield of a motor vehicle. FIG. 1b depicts a cross-sectional view of the windshield of FIG. 1a along the section line CC′. The windshield comprises a first pane 1, serving as an outer pane, and a second pane 2, as an inner pane. The inner pane is the pane directed toward the vehicle's interior, whereas the outer pane points toward the vehicle's surroundings. The first pane 1 and the second pane 2 are joined to one other via an intermediate layer 3. The first pane 1 has a thickness of 2.1 mm and is made of a green-colored soda lime glass. The second pane 2 has a thickness of 1.6 mm and is made of a clear soda lime glass. The laminated pane as a windshield has a front roof edge D facing the roof in the installed position and an engine edge M facing the engine compartment in the installed position.
[0125] The windshield is equipped with a functional element 5 as an electrically adjustable sun visor that is installed in a region above the central field of vision B (as defined in ECE-R43). The sun visor is formed by a commercially available PDLC multilayer film as a functional element 5, which is integrated into the intermediate layer 3. The height of the sun visor is, for example, 21 cm. The intermediate layer 3 comprises a total of three thermoplastic laminating films 6, 7, 8, which are in each case implemented as a thermoplastic film with a thickness of 0.38 mm made of PVB. The first thermoplastic laminating film 6 is bonded to the first pane 1; the second thermoplastic laminating film 7, to the second pane 2. The thermoplastic frame film 8 positioned therebetween has a cutout, into which the cut-to-size PDLC multilayer film is inserted with an exact fit, in other words, flush on all sides. The third thermoplastic layer thus forms, so to speak, a sort of passepartout for the functional element 5, which is thus encapsulated all around in a thermoplastic material and is protected thereby. The first thermoplastic laminating film 6 optionally has a tinted region 10 that is arranged between the functional element 5 and the first pane 1. The light transmittance of the windshield is thus additionally reduced in the region of the sun visor and the milky appearance of the PDLC functional element 5 is mitigated in the diffusive state. The aesthetics of the windshield thus become significantly more attractive. In the case shown, the lower edges of the tinted region and of the PDLC functional element 5 are arranged flush. This is, however, not necessarily the case.
[0126] The laminated pane according to the invention has, in its embodiment as a windshield of FIG. 1a, a circumferential masking print 9, which conceals both the adhesive connection of the windshield to the vehicle body and the electrical contacting of the flat electrodes of the functional element 5. The circumferential peripheral masking print 9 is implemented by an opaque enamel on the interior-side surfaces (facing the interior of the vehicle in the installed position) of the first pane 1 and the second pane 2. The distance of the functional element 5 from the front roof edge D and the side edges of the windshield is less than the width of the masking print 9 such that the side edges 4.1, 4.2, 4.4 of the functional element 5—with the exception of the side edge 4.3 pointing toward the central field of vision B—are concealed by the masking print 9. The electrical connections and the recesses of the separating lines are also reasonably attached in the region of the masking print 9 and thus advantageously concealed.
[0127] In a particularly convenient embodiment, the functional element 5 is controlled by a capacitive switch area arranged in the region of the sun visor, wherein the driver specifies the degree of darkening by means of the location at which he touches the pane. Alternatively, the sun visor can even be controlled by contactless methods, for example, by gesture recognition, or as a function of the pupil or eyelid state detected by a camera and suitable evaluation electronics.
[0128] The side edges of the functional element 5 are provided circumferentially with an edge seal (not shown) that is formed by a transparent acrylic adhesive tape. This prevents diffusion into or out of the active layer 11. Since the edge seal is transparent, the lower side edge, which is not concealed by the masking print 9, is also not distractingly visible. The edge seal runs circumferentially around the side edges of the multilayer film and extends, starting from the side edges, a few millimeters over the surfaces of the carrier films 14, 15 facing away from the active layer 11. The edge seal 10 prevents, in particular, the diffusion of plasticizers and other adhesive components of the thermoplastic frame film 8 into the active layer 11, as a result of which the aging of the functional element 5 is reduced.
[0129] A so-called “high flow PVB”, which has stronger flow behavior compared to standard PVB films, can preferably be used for the thermoplastic laminating films 6, 7 and the thermoplastic frame film 8. The layers thus flow more strongly around the functional element 5, creating a more homogeneous visual impression, and the transition from the functional element 5 to the frame film 8 is less conspicuous. The “high flow PVB” can be used for all or for only one or more of the thermoplastic films 6, 7, 8 having direct contact with the functional element 5.
[0130] FIG. 2a depicts a plan view of the functional element 5 of the windshield of FIG. 1a before integration of the functional element 5 into the windshield, wherein the electrical contacting of the functional element 5 can also be seen. FIGS. 2b and 2c depict cross-sections through the functional element of FIG. 2a along the section lines AA′ and BB′, respectively. The adjustable functional element 5 is a multilayer film, consisting of an active layer 11 between two flat electrodes 12, 13 and two carrier films 14, 15. The active layer 11 contains a polymer matrix with liquid crystals dispersed therein, which align themselves as a function of the electrical voltage applied to the flat electrodes, by which means the optical properties can be adjusted. The carrier films 14, 15 are made of PET and have a thickness of, for example, 0.125 mm. The carrier films 14, 15 are provided with a coating of ITO facing the active layer 11 and having a thickness of approx. 100 nm, which forms the first flat electrode 12 and the second flat electrode 13. The flat electrodes 12, 13 can be connected to the onboard electrical system via bus bars 18, 19 and connection cables (not shown). The bus bars 18, 19 are formed by a silver-containing screen print. The first flat electrode 12 has three separating lines 16 with, in each case, a width of 100 μm, introduced by means of a laser process, and which divide the first flat electrode 12 into four segments 17. The separating lines 16 run within the first flat electrode 12 between the side edges 4.2 and 4.4. At the side edge 4.2 that is formed by the first carrier film 14 with the first flat electrode 12, the separating lines 16 run all the way to this side edge 4.2. At the opposite side edge 4.4, the separating lines 16 run at least up to the edge of the first flat electrode 12 nearest the side edge 4.4. In practice, the separating lines 16 are preferably introduced continuously between the opposite side edges 4.2, 4.2, with the separating lines 16 also running through the region of the second bus bar 19, in which the first carrier film 14 with the first flat electrode 12 is removed. This causes no impairment of the function of the second bus bar 19 or the second flat electrode 13, but is easier to implement from a process technology standpoint. The separating lines 16 are spaced approximately 5 cm apart or, in the case of the segments at the edge, approximately 5 cm from the nearest side edge 4.1, 4.3. The side edges 4.1, 4.2, 4.3, 4.4 add up to form the circumferential edge of the functional element. The separating lines 16 electrically isolate the segments 17 from one another. The number of segments 17 can be freely selected depending on the application or customer requirements. The first flat electrode 12 has in each case one first bus bar 18 per segment 17, i.e., a total of four first bus bars 18. In the installed position of the functional element 5, the side edge 4.2 of the functional element 5, which accommodates the first bus bars 18, is arranged at a side edge of the windshield (adjacent the A-pillars of the vehicle body). The second bus bar 19, which makes electrically conductive contact with the second flat electrode 13, is attached at the side edge 4.4, which is opposite the side edge 4.2. In the installed position, the side edge 4.4 is also arranged adjacent an A-pillar of the vehicle body. The separating lines 16 run between the side edges 4.2, 4.4 within the first flat electrode 12. At the side edge 4.2, which carries the first bus bars 18, the separating lines 16 run between adjacent first bus bars 18 through to the side edge 4.2. Directly at the side edge 4.2, recesses introduced in the form of laser bores are introduced overlapping with each of the separating lines 16. Also, in the vicinity of the second bus bar 19 at a distance of approx. 1 mm from the second bus bar 19 and offset relative thereto in the direction of the surface center of the functional element 5, a recess 20 is situated in the region of each separating line 16. FIG. 2c depicts a cross-section along the section line BB′, which depicts the contacting of the bus bars 18, 19 on the flat electrodes 12, 13. The second carrier film 15, the second flat electrode 13, and the active layer 11 are removed in the region of the functional element 5 that is intended for the first bus bars 18. The first bus bars 18 are printed by screen printing onto the first flat electrode 12 thus exposed. The first bus bars 18 occupy a maximum possible width corresponding to the distance between adjacent separating lines 16 or between the separating line 16 and the side edge 4.1 or 4.3. Care must be taken to be sure that the bus bar 18 is printed exclusively within the associated segment 17, in order to prevent a short-circuit between adjacent segments 17. The second bus bar 19 ensures the electrical contacting of the second flat electrode 13. In this region of the second bus bar 19, the first carrier film 14 is removed with the first flat electrode 12 and the active layer 11. The side edge of the first carrier film 14 is set back in comparison with the side edge 4.4 in the region of the second bus bar 19 in the direction of the surface center of the functional element 5. In particular, at this set-back side edge of the first carrier film 14, defects of the separating lines 16 introduced in the first flat electrode 12 occur. The recesses 20 that are introduced into this region of the separating lines 16, provide electrical isolation of the defects, as a result of which leakage currents between the segments are avoided. All recesses 20 have a diameter of approx. 2 mm and are introduced by means of laser drilling, with the recess 20 penetrating at least the first carrier film 14 and the first flat electrode 12 in a circular manner along the contour of the recess 20. The recesses 20 adjacent the second bus bar 19 can also project into the active layer 11 or be manufactured as through-openings.
[0131] FIG. 3 depicts a plan view of an embodiment of a laminated pane according to the invention as a roof panel. The roof panel comprises a first pane 1, which serves as the outer pane, and a second pane 2, as the inner pane. Here, the inner pane is the pane facing the vehicle's interior, whereas the outer pane points toward the vehicle's surroundings. The first pane 1 and the second pane 2 are joined to one another via an intermediate layer 3. The first pane 1 is made of clear soda lime glass with a thickness of 2.1 mm. The second pane 2 is made of soda lime glass with a thickness of 1.6 mm and is tinted gray. The tinted inner glass contributes to the attractive appearance of the pane, even for the vehicle occupant when looking through the roof panel. The laminated pane as a roof panel has a front roof edge D in the installed position of the windshield and a rear roof panel D′ facing the rear pane in the installed position.
[0132] The roof panel is equipped with a functional element 5 as large-area shading, wherein the functional element is formed by a commercially available PDLC multilayer film that is integrated into the intermediate layer 3. The structure of the intermediate layer 3 corresponds essentially to that described in FIGS. 1a and 1b, when, in contrast thereto, the functional element extending in the entire through-vision region of the glazing. In the embodiment as a roof panel as well, the intermediate layer 3 is formed by the three thermoplastic laminating films 6, 7, 8, as described in FIGS. 1a and 1b. These are implemented in each case by a thermoplastic film with a thickness of 0.38 mm made of PVB. The first thermoplastic laminating film 6 is bonded to the first pane 1; the second thermoplastic laminating film 7, to the second pane 2. The thermoplastic frame film 8 positioned therebetween has a cutout, into which the cut-to-size PDLC multilayer film is inserted with an exact fit, i.e., flush on all sides. Depending on the thickness of the multilayer film and a resultant difference in thickness relative to the region without the functional element 5, the frame film 8 can be dispensed with. This is also dependent on the complexity of the bending of the laminated pane. Generally speaking, in the case of small differences in thickness between areas with a functional element and areas without a functional element and in the case of low complexity of the bending, a frame film can be dispensed with.
[0133] The first thermoplastic laminating film 6 and the second thermoplastic laminating film 7 are tinted gray in order to make the appearance of the roof panel attractive.
[0134] Optionally, an additional thermoplastic laminating film (not shown) can be introduced adjacent the outer pane (first pane 1). Carrier films with functional layers, for example, a carrier film with an infrared reflecting coating, can be incorporated via the additional thermoplastic laminating film. The infrared reflecting coating is oriented in the direction of the first pane 1 (outer pane) and serves to reduce the heating of the passenger compartment by solar radiation.
[0135] The roof panel according to the invention likewise has the circumferential masking print 9 already described for a windshield according to the invention, which conceals both the adhesive bond of the windshield to the vehicle body and the electrical contacting of the flat electrodes of the functional element 5. The distance of the functional element 5 from the front roof edge D, from the rear roof edge D′, and from the side edges of the roof panel is less than the width of the masking print 9 such that the side edges 4.1, 4.2, 4.3, 4.4 of the functional element 5 are concealed by the masking print 9. The electrical connections are also reasonably attached in the region of the masking print 9 and thus advantageously concealed.
[0136] FIG. 4a depicts a plan view of the functional element 5 of the roof panel of FIG. 3 before integration of the functional element 5 into the laminated pane, wherein the electrical contacting of the functional element 5 can also be seen. FIG. 4b depicts a cross-section through the functional element of FIG. 4a along the section line EE′; FIG. 4c depicts a cross-section along the section line FF′. The adjustable functional element 5 is a multilayer film, which corresponds in its composition to that described in FIG. 2a. The first flat electrode 12 has two separating lines 16 with a width in each case, of 100 μm, introduced by means of a laser process, and which divide the first flat electrode 12 into three segments 17. The distance between the separating lines depends on the size of the roof panel, with the through-vision region of the pane divided by the separating line 16 into three subregions roughly equal in area. The separating lines 16 electrically isolate the segments 17 from one another. The number of segments 17 can be freely selected depending on the application or customer requirements. The contacting of the segments 17 essentially corresponds to that described in FIGS. 2a, 2b, and 2c. In contrast thereto, the first flat electrode 12 has, in each case, two first bus bars 18 per segment 17, i.e., a total of 6 first bus bars 18. The first bus bars 18 associated with a segment 17 are situated at opposite side edges 4.2, 4.4 of the functional element 5.
[0137] The side edges 4.2, 4.4 of the functional element 5, which accommodate the first bus bars 18, are arranged, in the installed position of the functional element 5, at the side edges of the roof panel (above the side doors of the vehicle). A cross-section through the functional element of FIG. 4a along the section line FF′ corresponds in its schematic structure to that depicted in FIG. 4c. The contacting of the flat electrodes 12, 13 is basically analogous to that described in FIG. 2a, 2b, 2c. In contrast thereto, the separating lines 16 run through, on both side edges 4.2, 4.4 opposite one another between adjacent bus bars 18, with the side edges 4.2, 4.4 formed in each case by the first carrier film 14. The second carrier film 15 is, in each case, set back in the direction of the surface center of the functional element 5 at the side edges 4.2, 4.4. In each case, immediately adjacent the side edges 4.2, 4.4 in the region of the separating lines 16, a recess 20 is introduced at each separating line 16, electrically isolating possible defects of the separating lines 16. The recesses are implemented analogously to those described in FIG. 2a-2c. In contrast to the functional element 5 as a sun visor described in FIG. 2a, the functional element 5 of FIG. 4a provided for full-surface shading of a roof panel has an additional second bus bar 19. Since all side edges 4.1, 4.2, 4.3, 4.4 of the functional element are positioned outside the through-vision region of the pane and are concealed by the peripheral masking print 9, all side edges are available for contacting the flat electrodes. A second bus bar 19 is arranged at the front roof edge D of the roof panel. Another second bus bar 19 is arranged along the rear roof edge D′ at the opposite side edge 4.3 of the functional element 5. A cross-section along the section line EE′ of the functional element of FIG. 4a is depicted in FIG. 4b. The structure is analogous to that described in FIG. 2b, wherein, in contrast thereto, along two opposite side edges 4.1, 4.3 of the functional element 5, the first carrier film 14, the first flat electrode 12, and the active layer 11 are removed in one area in each case and one second bus bar 19 is printed in each case. The use of two second bus bars 19 and two first bus bars 18 in each case per segment 17 is advantageous in order to achieve uniform voltage distribution, even in the case of large dimensions of the functional element 5.
[0138] The distribution of a second bus bar and the group of first bus bars along the side edges 4.1, 4.2, 4.3, 4.4 can, in principle, be selected regardless of whether the functional element is a sun visor of a windshield or a large-area functional element of a roof panel and is described here only by way of example. However, in the case of a functional element as a sun visor, it should be noted that the side edge of the functional element pointing in the direction of the surface center of the windshield is located in the visible area of the pane and, for aesthetic reasons, should bear no bus bar. Regardless of this possible distribution of the bus bars along the pane edges, the recesses of the separating lines according to the invention are helpful in avoiding leakage currents between adjacent segments.
[0139] FIG. 5 depicts, using a flowchart, an exemplary embodiment of the production method according to the invention comprising the steps: [0140] I Providing a functional element 5, [0141] II Attaching a group of first bus bars 18 on the first flat electrode 12 and attaching at least one second bus bar 19 on the second flat electrode 13, [0142] III Introducing at least one separating line 16 into the first flat electrode 12 of the functional element 5 by means of a laser process, wherein the at least one separating line 16 divides the first flat electrode 12 into at least two segments 17, [0143] IV Introducing, in each case, at least two recesses 20 in the region of each of the separating lines 16 in the first flat electrode 12 by means of laser drilling, with the recesses 20 located in each case in the vicinity of an edge of the first flat electrode 12, at which bus bars 18, 19 are arranged, [0144] V Placing at least one first thermoplastic laminating film 6 on a first pane 1, placing the functional element 5 on the first thermoplastic laminating film 6, placing at least one second thermoplastic laminating film 7 on the functional element 5, and completing the layer stack with a second pane 2, [0145] VI Laminating the first pane 1 and the second pane 2 to form a laminated pane, wherein an intermediate layer 3 with an embedded functional element 5 is formed from the first thermoplastic laminating film 6 and the second thermoplastic laminating film 7.
[0146] The recesses 20 isolate the region of the first flat electrode 12 that is located within the recesses 20 from the region of the first flat electrode 12 that is located outside the recesses 20. Thus, the defect-prone regions of the separating lines 16 are electrically isolated and leakage currents between adjacent segments are avoided.
LIST OF REFERENCE CHARACTERS
[0147] 1 first pane [0148] 2 second pane [0149] 3 intermediate layer [0150] 4.1, 4.2, 4.3, 4.4 side edges [0151] 5 functional element with electrically adjustable optical properties [0152] 6 first thermoplastic laminating film [0153] 7 second thermoplastic laminating film [0154] 8 thermoplastic frame film [0155] 9 masking print [0156] 10 tinted region of the first thermoplastic laminating film [0157] 11 active layer of the functional element 5 [0158] 12 first flat electrode of the functional element 5 [0159] 13 second flat electrode of the functional element 5 [0160] 14 first carrier film [0161] 15 second carrier film [0162] 16 separating lines [0163] 17 segments [0164] 18 first bus bar [0165] 19 second bus bar [0166] 20 recess [0167] D front roof edge [0168] D′ rear roof edge [0169] M engine edge [0170] S side edges [0171] A-N, C-C′, E-E′, F-F′ section lines
