Glazing unit with electrically controllable optical properties with multiple independently switchable zones

Abstract

The invention relates to an assembly glass unit with a plurality of independent switching regions (S1, S2, S3, S4) with electrically controllable optical properties, comprising a composite glass pane with electrically controllable functional elements (4) and a control unit (10) suitable for controlling the optical properties of the functional elements (4). The functional elements (4) have an active layer (5) with electrically controllable optical properties between a first planar electrode (8) and a second planar electrode (9). The first planar electrode (8) is divided into at least two separate electrode sections (8.1, 8.2, 8.3, 8.4) by at least one insulating line (8'). An alternating voltage can be applied independently of one another between each electrode section (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) and the second planar electrode (9) in order to control the optical properties of the segment of the active layer (5) located therebetween. According to the invention, the control unit (10) is suitable for applying an alternating voltage each between at least two electrode sections (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand, wherein the alternating voltages are phase-shifted.

Description

[0001] The present invention relates to an assembled glazing unit with electrically controllable optical properties, its use and a method for controlling it.

[0002] Assembled glazing units with electrically controllable optical properties are known per se. They comprise a composite glass pane equipped with a functional element, the optical properties of which can be changed by applying a voltage. The voltage is applied by a control unit, which is connected to two planar electrodes of the functional element, between which an active layer of the functional element is located. One example of such a functional element is an SPD functional element (suspended particle device), which is known, for example, from EP 0876608 B1 and WO 2011033313 A1. The transmittance of visible light through the SPD functional element can be controlled by the applied voltage. Another example is a PDLC (polymer dispersed liquid crystal) functional element, which is known, for example, from DE 102008026339 A1. Here, the active layer contains liquid crystals embedded in a polymer matrix. If no voltage is applied, the liquid crystals are aligned randomly, which leads to a strong scattering of light through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals align in one common direction and the transmittance of light through the active layer increases. PDLC functional elements act less by increasing scattering than by reducing the overall transmittance, whereby uncontrolled see-through can be prevented or glare protection can be ensured. Furthermore, electrochromic functional elements are known, for example from US 20120026573 A1, WO 2010147494 A1 and EP 1862849 A1 and WO 2012007334 A1, in which a change in transmission takes place by an electrochemical process, which is induced by an applied voltage.

[0003] Such assembled glazing units can be used, for example, as vehicle glazing, the light transmission properties of which can be electrically controlled. For example, they can be used as sunroof glazing to reduce solar radiation or to reduce disturbing reflections. Such sunroof glazing is known, for example, from DE 10043141 A1 and EP 3456913 A1. Also proposed are windshields, in which an electrically controllable sun visor is realized by a switchable functional element instead of a mechanically foldable conventional sun visor in a motor vehicle. Windshields with electrically controllable sun visors are known, for example, from DE 102013001334 A1, DE 102005049081 B3, DE 102005007427 A1 and DE 102007027296 A1.

[0004] It is also known that such assembled glass units or switchable functional elements have a plurality of switching regions whose optical properties can be switched independently of one another. Thus, one region of the functional element can be selectively darkened or have a high light scattering, while other regions remain transparent. Assemblies glass units with independently switchable regions and methods for their manufacture are known, for example, from WO 2014072137 A1. Reference is also made to WO 2017157626 A1 and WO 2020083562 A1.

[0005] Independently switchable regions are usually formed by one of the planar electrodes being divided by insulating lines into regions (segments) separated from one another, which are each connected to the control unit independently of one another and can thus be controlled independently, while the other planar electrode is free of insulating lines. The insulating lines are usually introduced into the planar electrode by means of laser machining. The planar electrodes cannot be selected on the basis of optimum electrical conductivity, since they must be transparent in order to ensure the view through the composite glass pane. Usually, ITO layers are used as planar electrodes, which have a relatively low electrical conductivity or a relatively high electrical resistance. A problem arises when only some of the switching regions are supplied with a voltage. This voltage causes a current to flow through the active layer in the respective switching region, which in turn causes a potential shift of the unsegmented planar electrode due to its electrical resistance. This effect is also referred to as "ground shift". As a result, a certain voltage now also arises in those switching regions which should not actually be switched, which then likewise change their optical properties to some extent, which is undesirable. This effect is also referred to as cross talk between the switching regions. The "cross talk" therefore occurs particularly disturbingly, since the switching regions which are not activated and thus should be free of voltage are usually switched to the connection potential (reference potential, "ground") of the unsegmented planar electrode in order to ensure, on the one hand, a rapid discharge of the individual segments in the event of a deactivation thereof and, on the other hand, to avoid the effects of so-called "dirt resistance" (unwanted electrical connections due to dust or moisture). A closed circuit is thus formed through all the switching regions.

[0006] The "ground shift" is the more pronounced, the greater the number of switching regions which are "activated" (i.e. loaded with an intentional voltage). The "cross talk" effect therefore occurs particularly disturbingly in the case of a large number of activated switching regions.

[0007] In principle, the "cross talk" could be avoided by also segmenting the second planar electrode with respect to the switching regions by means of insulating lines. However, if both planar electrodes are to be segmented in one machining step, strong laser radiation is required for this, which reduces the aesthetic appearance of the composite glass pane, for example due to burn effects. Alternatively, if the two planar electrodes are to be segmented individually for this purpose, it is difficult to precisely coincide the insulating lines of the two planar electrodes. Furthermore, even in their fully coinciding arrangement, the "double" insulating lines in both planar electrodes are always more conspicuous visually than the insulating lines in only one planar electrode.

[0008] DE 102017213291 B3 discloses a control unit for a glazing unit with electrically controllable optical properties, which has a plurality of electrically potential-segmented circuit portions which can be operated in a phase-shifted manner. DE 102010056203 A1 likewise discloses a control unit for a glazing unit with electrically controllable optical properties. The problem of the above-mentioned "ground shift" and the resulting cross-talk between different switching regions is not addressed in these publications, nor is a solution proposed.

[0009] There is therefore a need for an improved glazing unit with electrically controllable optical properties with a plurality of independent switching regions, in which the "cross-talk" effect between activated and non-activated switching regions is avoided or at least significantly reduced. It is an object of the present invention to provide such an improved glazing unit and a control method therefor.

[0010] According to the invention, this object is achieved by a glazing unit with electrically controllable optical properties with a plurality of independent switching regions, which comprises a composite glass pane and a control unit. The composite glass pane comprises an outer glass pane and an inner glass pane which are connected to one another by means of a thermoplastic intermediate layer, and an electrically controllable functional element which is arranged between the outer glass pane and the inner glass pane. The functional element has an active layer with electrically controllable optical properties between a first planar electrode and a second planar electrode. The control unit is suitable for controlling the optical properties of the functional element. The first planar electrode is divided into at least two separate electrode segments by at least one insulating line. Each electrode segment of the first planar electrode and the second planar electrode are electrically connected to the control unit, so that an alternating voltage can be applied between each electrode segment of the first planar electrode and the second planar electrode independently of one another, in order to control the optical properties of the segment of the active layer which lies therebetween.

[0011] According to the invention, the control unit is suitable for applying one alternating voltage each between, on the one hand, the at least two electrode segments of the first planar electrode and, on the other hand, the second planar electrode, wherein the alternating voltages are phase-shifted (have a phase shift from one another). The suitability of the control unit is manifested, inter alia, in that a software which regulates the control of the alternating voltages according to the invention is stored, and it has the hardware components necessary for storing this software and for executing it as intended. The software control is technically easy to implement and is therefore preferred. Alternatively, however, the control of the alternating voltages can also be carried out purely by means of suitable hardware components. The suitability is then manifested in the corresponding design of the hardware components. The control unit is designed, inter alia, for applying one alternating voltage each between, on the one hand, the at least two electrode segments of the first planar electrode and, on the other hand, the second planar electrode, wherein the alternating voltages are phase-shifted. The control unit is correspondingly configured and the glazing unit is operated in this way.

[0012] This object is also achieved by a method for controlling an assembly glazing according to the application with a plurality of independently switchable switching regions. The method according to the application is characterized in that between at least two electrode segments of a first planar electrode on the one hand and a second planar electrode on the other hand each one alternating voltage is applied, wherein the alternating voltages are phase-shifted with respect to one another.

[0013] In the following the assembly glazing and the method are introduced together, wherein the explanations and preferred embodiments relate to both the assembly glazing and the method. If preferred features are described in connection with the method, it follows that the respective features are also preferred for the assembly glazing and are designed accordingly and are suitable for the assembly glazing. Conversely, if preferred features are described in connection with the assembly glazing, it follows that the method is also preferably carried out accordingly.

[0014] The application is based on the recognition that the disturbing effect of "cross-talk", i.e. the phenomenon that the switching state of an activated switching region appears to radiate to other switching regions which are actually voltage-free, is caused by a potential shift of the reference potential of the second planar electrode due to the current flow into the activated switching region. The core of the application is now to operate the activated switching region with a phase-shifted alternating voltage, so that the potential shift is completely or at least partially compensated by a counter current. In this way, an undesired switching of the actually non-activated switching regions can be prevented or at least reduced. Furthermore, the solution according to the application is relatively easy to implement, since the phases of the alternating voltages can be determined individually by a control unit and no structural changes to the composite pane have to be made. These are great advantages of the application.

[0015] The composite pane according to the application comprises at least one outer glass pane and one inner glass pane, which are connected to one another by means of a thermoplastic intermediate layer. The composite pane provides for separating an interior space from an exterior environment in a window opening, in particular a window opening of a vehicle, but also a window opening of a building or a room. In the sense of the application, the inner glass pane refers to the glass pane which faces the interior space. The outer glass pane refers to the glass pane which faces the exterior environment. The outer glass pane and the inner glass pane each have an outer side and an interior space side surface and a circumferential side edge surface extending therebetween. In the sense of the application, the outer side surface refers to that main face which provides for facing the exterior environment in the installed position. In the sense of the application, the interior space side surface refers to that main face which provides for facing the interior space in the installed position. The interior space side surface of the outer glass pane and the outer side surface of the inner glass pane face one another and are connected to one another by means of the thermoplastic intermediate layer.

[0016] The composite glass pane according to the application comprises a functional element having electrically controllable optical properties, which is arranged between the outer glass pane and the inner glass pane, i.e. embedded in the intermediate layer. The functional element is preferably arranged between at least two layers of thermoplastic material of the intermediate layer, wherein it is connected to the outer glass pane by means of the first layer and to the inner glass pane by means of the second layer. Alternatively, however, the functional element can also be arranged directly on the surface of the outer glass pane or the inner glass pane facing the intermediate layer. The side edges of the functional element are preferably completely surrounded by the intermediate layer, so that the functional element does not extend to the side edges of the composite glass pane and thus does not come into contact with the surrounding atmosphere.

[0017] The functional element comprises at least one active layer and two planar electrodes, which are arranged on both sides of the active layer, so that the active layer is arranged between the planar electrodes. The planar electrodes and the active layer are generally arranged substantially parallel to the surfaces of the outer glass pane and the inner glass pane. The active layer has variable optical properties, which can be controlled by means of a voltage applied to the active layer via the planar electrodes. In the sense of the present application, electrically controllable optical properties are understood in particular to mean those properties which can be controlled steplessly. In the sense of the present application, the switching state of the functional element here denotes the degree of change in the optical properties relative to the voltage-free state. A switching state of 0% corresponds to the voltage-free state, and a switching state of 100% corresponds to the maximum change in the optical properties. By means of a suitable selection of the voltage, all switching states can be achieved steplessly therebetween. For example, a switching state of 20% corresponds to a change in the optical properties of 20% of the maximum change. The optical properties relate in particular to the light transmission and / or scattering behavior.

[0018] However, it is also conceivable in principle that the electrically controllable optical properties can only be switched between two discrete states. There are then only two switching states, namely 0% and 100%. It is likewise conceivable that the electrically controllable optical properties can be switched between more than two discrete states.

[0019] The planar electrodes are preferably transparent, which in the sense of the present application means that they have a light transmission in the visible spectral range of at least 50%, preferably at least 70%, particularly preferably at least 80%. The planar electrodes preferably comprise at least one metal, metal alloy or transparent conducting oxide (TCO). The planar electrodes can be formed, for example, on the basis of silver, gold, copper, nickel, chromium, tungsten, indium tin oxide (ITO), gallium-doped or aluminum-doped zinc oxide and / or fluorine-doped or antimony-doped tin oxide, preferably on the basis of silver or ITO. The planar electrodes preferably have a thickness of 10 nm to 2 pm, particularly preferably 20 nm to 1 pm, very particularly preferably 30 nm to 500 nm.

[0020] According to the application, the first planar electrode has at least two segments (electrode segments) separated from one another by insulating lines. Insulating lines are understood to be line-shaped regions in which there is no material of the planar electrode, so that adjacent segments are separated from one another in terms of substance and are thus electrically insulated from one another. This means that there is no direct electrical connection between the electrode segments, whereas the electrode segments can be indirectly electrically connected to one another to some extent via the active layer with which they are in contact. The first planar electrode can be divided into a plurality of segments by a plurality of insulating lines. Each electrode segment forms one switching region of the glazing. The number of electrode segments can be freely selected by the person skilled in the art depending on the requirements of the specific case. In one preferred embodiment, the insulating lines extend substantially parallel to one another and from one side edge of the planar electrode to the opposite side edge. However, any other geometry is also conceivable.

[0021] In an advantageous embodiment, the first planar electrode has at least three electrode segments, which are separated from one another by one insulating line each. Thus, there are at least two insulating lines in total, and the glazing has at least three independent switching regions. Although a glazing with only two switching regions can also be operated with a phase-shifted alternating voltage according to the principle of the application without any problems. However, since there is then no other switching region which can have a switching state of 0% and on which the “crosstalk” effect can act as an interference, the application does not unfold its full potential in this case. For the same reason, the method according to the application is particularly advantageous if not all switching regions are activated, but there is a switching state of more than 0% in at least two switching regions and at least one switching region has a nominal switching state of 0%.

[0022] However, the application can also be used for a glazing with only two independent switching regions. If there are two or more switching regions, in which all switching regions are activated, i.e. have a switching state of more than 0%, the method can also be used. In particular, the accuracy of the switching state can be improved depending on the case. In addition to the particularly disruptive “crosstalk”, i.e. the undesired switching of a switching region which is not actually activated, the potential offset of the second planar electrode has another negative effect: since the voltage magnitude, i.e. the difference between the switching potential of the first planar electrode and the reference potential of the second planar electrode, deviates from the value set by the user due to the potential offset, the desired switching state is sometimes not set exactly - the actual switching state deviates from the set switching state. This can occur particularly disruptively when the switching state is less than 100%, so that the switching region is as it were “fuzzy”, since in this case the voltage value has to be set very precisely. Thus, for example, the application can be used to improve the accuracy of the switching state of more than 0% and less than 100% of a switching region by compensating for the contribution to the potential offset of the second planar electrode caused by the remaining switching regions for one another due to the phase shift.

[0023] The insulating lines have a width of, for example, 5 pm to 500 pm, in particular 20 pm to 200 pm. They are introduced into the planar electrode, preferably by means of laser radiation. The width of the segments, i.e. the spacing of adjacent insulating lines, can be chosen as desired by the person skilled in the art depending on the specific case.

[0024] The second planar electrode and the active layer are preferably each formed as a continuous, complete layer which is not divided into segments by insulating lines. However, it is also conceivable in principle that the degree of segmentation of the second planar electrode is less than that of the first planar electrode, i.e. there are fewer insulating lines and electrode segments, so that at least one electrode segment of the second planar electrode is assigned a plurality of electrode segments of the first planar electrode. In this case, too, the problem of “cross talk” arises, which can be reduced by the method according to the application. In this case, the technical teaching according to the application relates to each segment of the second planar electrode, to which electrode segments of the first planar electrode are assigned, independently of the other segments.

[0025] The electrode segments of the first planar electrode are each independently of the other electrically connected to the control unit, so that a first potential, which changes over time in the case of an alternating voltage, can be applied to each electrode segment (independently of the other electrode segments), which is referred to as the switching potential in the sense of the application. The second planar electrode is likewise electrically connected to the control unit, so that a second potential can be applied to the second planar electrode as a whole, which is referred to as the reference potential (“ground”) in the sense of the application. If the first and second potentials are identical, there is no voltage between the electrodes in the respective switching region (switching state 0%). If the first and second potentials are different, there is a voltage between the electrodes in the respective switching region, as a result of which a finite switching state arises.

[0026] The control unit provides for and is suitable for controlling the optical properties of the functional element. The control unit is electrically conductively connected on the one hand to the planar electrode of the functional element and on the other hand to a voltage source. The voltage source provides a primary voltage. The control unit contains the required electrical and / or electronic components in order to apply the required voltages to the planar electrode depending on the switching state. The switching state can be predetermined here by the user (for example, by operating a switch, a button or a rotary or slide control), determined by a sensor and / or transmitted via a digital interface of a central control instrument of the vehicle (if the composite glass pane is a vehicle glass pane, usually a LIN bus or a CAN bus). For example, if the composite glass pane is a vehicle glass pane, the switch, button or rotary or slide control can be integrated into the dashboard of the vehicle. However, a touch switch surface can also be integrated directly into the composite glass pane, for example a capacitive or resistive switch surface. Alternatively, the functional element can also be controlled by contactless methods, for example by recognizing gestures, or depending on the state of the pupils or eyelids determined by a camera and suitable evaluation electronics. The control unit can comprise, for example, an electronic processor, transformers, transistors and other components.

[0027] According to the application, the voltage applied to the planar electrode is an alternating voltage. In a preferred embodiment, the voltage source is a direct voltage source. The primary voltage is therefore a direct voltage. This is the case, for example, in a vehicle when the composite glass pane is a vehicle glass pane and the control unit is connected to the on-board voltage. The control unit is preferably connected here to the vehicle body electrical system, from which it in turn obtains the voltage and optionally information about the switching state. The control unit is then equipped with a plurality of inverters in order to convert the direct voltage into an alternating voltage. The number of inverters corresponds at least to the number of electrode segments of the first planar electrode, so that each electrode segment is assigned its own inverter. Here, the assignment of inverters and electrode segments is one-to-one: each electrode segment is connected to exactly one inverter and each inverter is connected to exactly one electrode segment. By "connected" is meant that the two components are electrically conductively connected to one another, so that a potential can be transmitted to the electrode or electrode segment.

[0028] If the primary voltage is sufficiently high to control the functional element, it can be converted directly into an alternating voltage. However, since the on-board voltage of the vehicle (for example 12 to 14 V) is usually not sufficient to fully switch the functional element, the control unit is furthermore preferably equipped with a DC voltage transformer which is suitable to increase the supplied supply voltage (primary voltage), that is to say to convert it into a higher secondary voltage (for example 65 V). The control unit is connected to a DC voltage source and supplied with the primary voltage thereby. The primary voltage is converted into a higher secondary voltage by means of the DC voltage transformer. The secondary voltage is converted into an alternating voltage (for example effective 48 V) by means of an inverter which is suitable therefor. The alternating voltage is then applied to the electrode segments of the first planar electrode on the one hand and to the second planar electrode on the other hand.

[0029] In an advantageous embodiment, the secondary voltage is 65 to 70 V and the alternating voltage is 48 to 50 V (each effective). These values are to be understood as maximum values for a 100% switching state. In order to achieve a switching state of less than 100%, then naturally lower voltages are required.

[0030] According to the application, the switching regions are supplied with independent alternating voltages, wherein the alternating voltages of the different switching regions can have a phase shift from one another. In an advantageous embodiment, this is achieved in that the reference potential applied to the second planar electrode is constant over time. Each electrode segment of the first planar electrode is supplied with a switching potential which changes over time. For each switching region, the alternating voltage results as a time-varying difference between the switching potential and the reference potential. The magnitude and the phase of the alternating voltage of the different switching regions can thus be set independently of one another by selecting the magnitude and the phase of the respective switching potential.

[0031] The change of the switching potential over time can for example be sinusoidal, rectangular or triangular, whereby it generates a sinusoidal voltage, a rectangular wave voltage or a triangular wave voltage. The alternating voltage used is particularly preferably a sinusoidal voltage, that is to say the switching potential is sinusoidally modulated. A sinusoidal voltage is particularly advantageous in terms of current consumption and electromagnetic compatibility.

[0032] The independent alternating voltages of the individual switching regions can be realized in a variety of ways. In a first preferred embodiment, the number of inverters corresponds to the number of electrode segments of the first planar electrode. On the one hand, each inverter is connected (in electrically conductive connection) with exactly one electrode segment of the first planar electrode. On the other hand, each inverter is connected with the second planar electrode. In other words, each electrode segment of the first planar electrode is connected with a respective own inverter which is not connected with other electrode segments, and the second planar electrode is connected with all inverters. The reference potential applied by the inverters to the second planar electrode is preferably the same for all inverters and constant over time. The switching potentials applied by the inverters to the individual electrode segments of the first planar electrode change over time and can have values independent of one another and phases independent of one another. In this way, the independent alternating voltages of the switching regions according to the application can be realized with the phase shifts according to the application.

[0033] In a second preferred embodiment, the number of inverters is one more than the number of electrode segments of the first planar electrode. If the number of electrode segments is m, where m is a natural number, then the number of inverters is (m + 1). Each electrode segment of the first planar electrode is connected (in electrically conductive connection) with its own inverter which is not connected with other electrode segments. The second planar electrode is likewise connected with its own inverter which is not connected with the electrode segments of the first planar electrode. In other words, each inverter is assigned to and connected with exactly one electrode segment or exactly one electrode selected from the second planar electrode and all electrode segments of the first planar electrode. The reference potential applied by the inverters to the second planar electrode is preferably constant over time. The switching potentials applied by the other inverters to the different electrode segments of the first planar electrode change over time and can have values independent of one another and phases independent of one another. In this way, the independent alternating voltages of the switching regions according to the application can be realized with the phase shifts according to the application.

[0034] In the sense of the application, the said number of inverters of the control unit relates to the actually used inverters connected to the planar electrodes. That is to say, it means the effective number of inverters switched on. It is naturally conceivable that the control unit has further inverters, but these are not connected to the planar electrodes and thus do not participate in the switching process. Thus, for example, a control unit with a large number of inverters can be provided as a standard component, in which case then, depending on the number of switching regions thereof, only the number of inverters required for the assembly of the glass unit in the specific application case is occupied. In this way, it is not necessary to design the control unit for the specific application case respectively.

[0035] The functional element is preferably operated by the control unit in such a way that the electrode segments of the first planar electrode are subjected to a potential corresponding to the nominal potential of the second planar electrode in those switching regions which have a switching state of 0%. An undesired "cross-talk" then occurs as a result of the described potential offset ("ground shift") of the second planar electrode. In this type of line, all switching regions form a closed circuit involving all electrode segments of the first planar electrode and the second planar electrode. This is advantageous in terms of fast switching performance as a result of the rapid discharge of the individual switching regions. In addition, the disturbing influence of the so-called "dirt tolerance" (unwanted electrical connections as a result of dust or moisture) is avoided.

[0036] According to the application, it is intended to avoid or reduce the potential offset ("ground shift") of the reference potential by means of a counter current, which is achieved by a phase shift of the alternating voltage of the active switching regions (i.e. switching regions whose switching state is desired to be greater than 0%). This principle can be implemented in different ways.

[0037] In a first preferred embodiment, the active switching regions are divided into two groups, which are each operated with a phase-locked alternating voltage, wherein the alternating voltages of the two groups have a phase shift of 180° with respect to one another. If the number of active switching regions is even, the two groups are chosen to be of the same size, such that the counter currents ideally compensate one another and avoid a "ground shift". This applies at least in the case where the switching states (in total) of the two groups are identical and thus the magnitudes (in total) of the alternating voltages are identical. If one group has a higher voltage as a result of a higher switching state, an effective residual current remains uncompensated, which in terms leads to a "ground shift". However, this "ground shift" is significantly less pronounced compared to when all switching regions are operated with a phase-locked alternating voltage. If the number of active switching regions is odd, the groups are chosen in such a way that one group has exactly one more switching region than the other group. Assuming that the switching states and the voltage magnitudes of all switching regions are identical, the currents of all switching regions of the larger group are compensated by the counter currents of the switching regions of the smaller group, except for exactly one. The uncompensated current of this switching region of the larger group then leads to an effective residual "ground shift", which is, however, significantly less pronounced compared to when all switching regions are operated with a phase-locked alternating voltage - thus, the "ground shift" is significantly reduced.

[0038] In the above first preferred embodiment, in one aspect n electrode segments of the first planar electrode and in another aspect the second planar electrode are respectively supplied with an alternating voltage to produce a finite switching state of more than 0%. In this case, n is an integer greater than zero, corresponding to the number of active switching regions. The n electrode segments are the electrode segments of these active switching regions. If n is even, n / 2 electrode segments of the first planar electrode in one aspect and the second planar electrode in another aspect are supplied with an alternating voltage having a first phase. Likewise, the remaining n / 2 electrode segments of the first planar electrode in one aspect and the second planar electrode in another aspect are supplied with an alternating voltage having a second phase. If n is odd, (n+1) / 2 electrode segments of the first planar electrode in one aspect and the second planar electrode in another aspect are supplied with an alternating voltage having a first phase. Likewise, the remaining ((n-1) / 2 electrode segments of the first planar electrode in one aspect and the second planar electrode in another aspect are supplied with an alternating voltage having a second phase. In both cases, the first phase and the second phase have a phase shift of 180°.

[0039] The phase shift of 180° described is optimal and leads to complete compensation of the reverse current. However, significant improvements can also be obtained with slight deviations from this optimum value. Here, the phase shift is preferably 150° to 210°, particularly preferably 160° to 200°, very particularly preferably 170° to 190° and ideally 180°.

[0040] Strictly speaking, the above-described embodiment is only suitable for the case in which all switching regions have the same size, since the voltage required for a specific switching state also depends on the size and geometry of the switching regions. In typical application cases, this is at least approximately the case. In contrast, if the areas of the switching regions differ very greatly, they can be grouped differently in order to achieve the best possible compensation of the contribution to the "ground shift" according to the principle of the application, wherein, for example, a plurality of smaller switching regions are combined to compensate for a larger switching region.

[0041] For each switching situation, the switching area groups can be formed by the control unit under software control in such a way that the size of the groups fulfils the above-mentioned rule. Upon changing the switching situation, for example caused by a user input, the control unit determines the number of switching areas to be activated and groups them in order to compensate the current flow and thus avoid or reduce the potential shift of the second planar electrode. However, since adjacent switching areas are usually activated in typical application situations, the switching areas can alternatively be fixedly divided into the groups and assigned to the fixed phases of the electrode segments from the outset. This is especially suitable in the case of electrode segments extending from one side edge of the functional element to the opposite side edge and arranged substantially parallel to each other. For example, if the functional element forms an electrically controlled sun visor of a windscreen, the user will usually darken or provide with high light scattering the continuous area of the functional element adjacent to the side edge of the functional element facing the windscreen, the height depending on the position of the sun. The functional element is then divided into a first continuous area adjacent to the side edge facing the upper edge, which is formed by adjacent activated switching areas, and a second continuous area adjacent to the side edge facing away from the upper edge, which is formed by adjacent non-activated switching areas. Similar situations occur, for example, in the case of a sunroof glass with switching areas extending between the side edges of the sunroof glass and having different distances to the front or rear edge. Depending on the position of the sun, there is usually also a first continuous area here, which faces the front edge of the sunroof glass and is formed by adjacent activated (or non-activated) switching areas, and a second continuous area, which faces the rear edge of the sunroof glass and is formed by non-activated (or activated) switching areas adjacent to each other. The fixed phases of the alternating voltage can thus be assigned to each electrode segment of the first planar electrode, wherein the alternating voltage of adjacent electrode segments (or switching areas) is phase-shifted by 180° in each case. The alternating voltage between directly adjacent electrode segments of the first planar electrode and the second planar electrode is thus phase-shifted by 180° in each case. One advantage of the phase shift of adjacent electrode segments is also a more uniform phase distribution, since the "ground shift" of the second planar electrode is not uniform, but spatially distributed differently.

[0042] In the case of very different switching states of the activated switching regions, it is conceivable in an extension of the first preferred embodiment that the groups of switching regions (or electrode segments) are not formed according to the above-mentioned rule, but that they are formed flexibly depending on the switching states and the voltage magnitudes required therefor, in order to make the total voltage magnitudes of each group as similar as possible. Here, the assignment is thus not made according to the number of switching regions, so that the groups comprise the same or as similar a number of switching regions as possible. Instead, the groups are assigned in such a way that the difference between the total voltage magnitudes of two groups is as small as possible. For example, a plurality of switching regions with low switching states are combined into one group in order to compensate for one switching region with a high switching state. Here, different sizes of the switching regions can also be taken into account. The assignment can be made software-controlled and, in the case of very different switching states (and / or very different sizes) of the individual switching regions, the best compensation of the "ground drift" can also be ensured by a similar intensity of the counter-currents.

[0043] In the second preferred embodiment, all active switching regions are each operated with an alternating voltage of their own, i.e. different from the other switching regions. There is thus a phase shift between each arbitrarily chosen pair of switching regions. Here, the choice of the phase shift depends on the number of active switching regions - it is 360° divided by the number of switching regions or an integer multiple thereof. This avoids the "ground drift", since the currents are ideally compensated. This is at least true in the case of identical switching states of the different switching regions and thus identical magnitudes of the alternating voltages. Otherwise, the currents can only be partially compensated, but the "ground drift" is still at least significantly reduced. The compensation is particularly ideal when the alternating voltages are sinusoidal voltages.

[0044] In the second preferred embodiment, in each case one alternating voltage with its own, i.e. different from the other electrode segments, phase is applied between the n electrode segments of the first planar electrode on the one hand and the second planar electrode on the other hand, in order to produce a finite switching state greater than 0%. n is again an integer, corresponding to the number of active switching regions. The alternating voltages have a phase shift from one another of or an integer multiple thereof. Thus, no phase occurs more than once, i.e. for more than one electrode segment. For each electrode segment, there is exactly one electrode segment with a phase shift of and, if n is greater than 2, exactly one electrode segment with a phase shift of and, if n is greater than 3, exactly one electrode segment with a phase shift of and so on. In general, the phase shift of the alternating voltage of the i-th electrode segment with respect to the alternating voltage of the first active electrode segment is calculated from where n is the total number of active segments.

[0045] ​Due to the spatial inhomogeneity of the earth's drift, it is advantageous when the phases of adjacent segments are formed as differently as possible. The phase shift is therefore chosen such that the phase shift of the respective adjacent segments is maximally formed. In another preferred embodiment, the phase shift of the i-th segment is then calculated with respect to the phase shift of the first active electrode segment The phase shift of the alternating voltage of the i-th electrode segment with respect to the alternating voltage of the first active electrode segment where n is the total number of active segments and i is their spatial sequential number. "mod" denotes the modulo operation. In principle, however, the phase shifts of the adjacent activated switching regions can also each be while the switching regions that are not directly adjacent have a phase shift that is a multiple of of the phase shift of the first active electrode segment.

[0046] The phase shift of the alternating voltage of the i-th electrode segment with respect to the alternating voltage of the first active electrode segment is optimal and leads to a complete compensation of the counter current. However, significant improvements can also be achieved when deviating slightly from this optimum. Here, the phase shift is preferably to , particularly preferably to , very particularly preferably to and ideally .

[0047] In the case of a large number of activated switching regions, in an extension of the second preferred embodiment, the activated switching regions can be divided into more than two groups, wherein all groups preferably have the same number of switching regions or at least as similar a number as possible, such that the number of switching regions of the different groups differs by at most 1. Each group is operated with a phase-locked alternating voltage, the alternating voltages of the different groups having a phase shift of 360° divided by the number of groups or an integer multiple thereof. Good compensation of the "earth offset" can also be achieved in this way. Due to the spatial inhomogeneity of the "earth drift" already mentioned, it is particularly advantageous here to choose the groups such that their members have as large a spacing as possible in space.

[0048] In both preferred embodiments, the best effect is achieved when all switching regions have the same size, since the voltage required for a specific switching state also depends on the size and geometry of the switching regions. In typical application cases, this is at least approximately the case. It is therefore particularly advantageous if all switching regions have at least approximately the same area, wherein the area of the individual switching regions differs from the average of the areas of all switching regions by at most 20%, preferably at most 10%.

[0049] Likewise, the best effect is achieved in both preferred embodiments if all switching regions are operated with an alternating voltage of the same amplitude, so this is likewise an advantageous case.

[0050] Various functional elements can be used, as long as they operate with alternating voltage. In a preferred embodiment, the functional element is a PDLC (Polymer Dispersed Liquid Crystal) functional element. The active layer of a PDLC functional element comprises liquid crystals embedded in a polymer matrix. If no voltage is applied to the planar electrodes, the liquid crystals are aligned in a disordered manner, which leads to a strong scattering of light through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals align along one common direction and the transmission of light through the active layer increases. However, other liquid crystal-based functional elements whose variability of optical properties can be used, such as PNLC (Polymer Network Liquid Crystal) functional elements.

[0051] In another preferred embodiment, the functional element is an SPD functional element (Suspended Particle Device). Here, the active layer contains suspended particles, wherein the absorption of light by the active layer can be changed by means of applying a voltage to the planar electrodes.

[0052] The mentioned controllable functional elements and their mode of operation are known per se to the person skilled in the art and a detailed description can therefore be omitted here.

[0053] In an advantageous embodiment, the functional element comprises, in addition to the active layer and the planar electrodes, two carrier films, wherein the active layer and the planar electrodes are preferably arranged between the carrier films. The carrier films are preferably formed from thermoplastic materials, such as based on polyethylene terephthalate (PET), polypropylene, polyvinyl chloride, fluorinated ethylene-propylene, polyvinyl fluoride or ethylene-tetrafluoroethylene, particularly preferably based on PET. The thickness of the carrier films is preferably 10 pm to 200 pm. Such a functional element can advantageously be provided as a multilayer film, in particular purchased, cut to the desired size and shape and then laminated into the composite glass pane, preferably with one thermoplastic connecting layer each to the outer and inner glass pane. The first planar electrode can be segmented by means of laser radiation, even when it is embedded in such a multilayer film. By means of laser machining, fine, optically inconspicuous insulation lines can be produced without damaging the carrier films, which are usually located thereabove.

[0054] The side edges of the functional element can be sealed, for example by fusing the carrier layers or by a (preferably polymeric) tape. In this way, the active layer can be protected, in particular from diffusion of components of the interlayer, in particular plasticizers, into the active layer, which can lead to degradation of the functional element.

[0055] For electrical contacting of the planar electrodes or electrode segments, they are preferably connected with so-called flat conductors or foil conductors which extend beyond the side edges of the composite glass pane from the interlayer. The flat conductors have a strip-shaped metal layer as the electrically conductive core, which is usually surrounded by a polymer insulating sheath, with the exception of the contact surface. Optionally, so-called bus bars, for example electrically conductive foil strips, for example copper foil, or electrically conductive prints, can be arranged on the planar electrodes, to which the flat conductors or foil conductors are connected. The flat conductors or foil conductors are connected with the control unit, directly or via further conductors.

[0056] In an advantageous embodiment, the control unit is fixed on the interior space-side surface of the inner glass pane which faces away from the interlayer. For example, the control unit can be directly adhered to the surface of the inner glass pane. In an advantageous embodiment, the control unit is inserted into a fixing element which in turn is fixed to the interior space-side surface of the inner glass pane, preferably by means of an adhesive layer. Such fixing elements are also referred to as "holders" in the field of vehicles and are usually made of plastic. By mounting the control unit directly on the composite glass pane, the electrical connections can also be made easier. In particular, long electrical cables are not required between the control unit and the functional elements.

[0057] Alternatively, however, the control unit can also not be fixed on the composite glass pane, but for example integrated in the electrical system of the vehicle or, if the composite glass pane is a vehicle glass pane, fixed on the vehicle body of the vehicle. The control unit is preferably arranged in a non-visible manner in the interior space of the vehicle, for example in the dashboard or behind a wall covering.

[0058] The composite glass pane can be equipped with an opaque cover print, in particular in the surrounding edge region, as is customary in the field of vehicles, in particular for the windshield, rear window and roof window. The cover print is usually formed from an enamel which contains frit and pigments, in particular black pigments. The printing ink is usually applied in a silk screen printing process and baked. Such a cover print is applied to at least one glass pane surface, preferably to the interior space-side surface of the outer glass pane and / or of the inner glass pane. The cover print preferably surrounds the central see-through region in a frame-like manner and serves in particular for protecting the adhesive by which the composite glass pane is connected with the vehicle body from UV radiation. If the control unit is mounted on the interior space-side surface of the inner glass pane, it is preferably in the opaque region of the cover print.

[0059] The thermoplastic interlayer is used to connect two glass sheets, as is common for composite glass sheets. Usually, thermoplastic films are used and form the interlayer. In a preferred embodiment, the interlayer is formed at least from a first thermoplastic layer and a second thermoplastic layer, between which the functional element is arranged. The functional element is then connected to the outer glass sheet via one region of the first thermoplastic layer and to the inner glass sheet via one region of the second thermoplastic layer. The thermoplastic layers preferably surround the functional element beyond. Where the thermoplastic layers are in direct contact with each other and are not separated from each other by the functional element, they can fuse during the lamination process, so that the original layers can no longer be identified, but a uniform interlayer is present.

[0060] The thermoplastic layers can be formed, for example, from a single thermoplastic film. The thermoplastic layers can also be formed from segments of different thermoplastic films, which side edges are placed together.

[0061] In a preferred embodiment, the functional element, more precisely the side edges of the functional element, is surrounded by a third thermoplastic layer. The third thermoplastic layer is formed in a frame-like manner, with a recess into which the functional element is fitted. The third thermoplastic layer can be formed from a thermoplastic film, in which the recess has been introduced by cutting it. Alternatively, the third thermoplastic layer can also consist of a plurality of film segments that surround the functional element. The interlayer is then formed from a total of at least three thermoplastic layers arranged planar to each other, wherein the middle layer has a recess into which the functional element is arranged. In manufacture, the third thermoplastic layer is arranged between the first and second thermoplastic layers, wherein the side edges of all thermoplastic layers preferably coincide. The third thermoplastic layer preferably has approximately the same thickness as the functional element. Thereby, local thickness differences introduced by the positionally adjacent functional elements are compensated, so that glass breakage during lamination can be avoided and the visual appearance is improved.

[0062] The layers of the interlayer are preferably formed from the same material, but in principle can also be formed from different materials. The layers or films of the interlayer are preferably based on polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) or polyurethane (PU). This means that the layers or films mainly contain the stated material (in a proportion of more than 50% by weight) and can optionally also contain further components, such as plasticizers, stabilizers, UV absorbers or IR absorbers. The thickness of each thermoplastic layer is preferably 0.2 mm to 2 mm, particularly preferably 0.3 mm to 1 mm. For example, films with a standard thickness of 0.38 mm or 0.76 mm can be used.

[0063] The outer glass pane and the inner glass pane are preferably made of glass, particularly preferably of soda-lime glass, as is customary for glazing. However, the glass panes can also be made of other types of glass, for example quartz glass, borosilicate glass or aluminosilicate glass, or of rigid, transparent plastics, for example polycarbonate or polymethyl methacrylate. The glass panes can be colorless and transparent, colored or tinted. Depending on the application, there can be restrictions on the degree of coloring or tinting: Thus, it is sometimes necessary to ensure a specified light transmission, for example at least 70% in the main perspective area A, in accordance with the United Nations Economic Commission for Europe (UN / ECE) Regulation No. 43 (ECE-R43, "Einheitliche Bedingungen die Genehmigung der Sicherheitsverglasungswerkstoffe und ihres Einbaus in Fahrzeuge").

[0064] The outer glass pane, the inner glass pane and / or the intermediate layer can have suitable coatings known per se, for example anti-reflection coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings, UV-absorbing or -reflecting coatings or IR-absorbing or -reflecting coatings, such as solar-protection coatings or low-E coatings.

[0065] The thickness of the outer glass pane and the inner glass pane can vary widely and can thus be adapted to the requirements of the specific case. The thickness of the outer glass pane and the inner glass pane is preferably from 0.5 mm to 5 mm, particularly preferably from 1 mm to 3 mm.

[0066] The application also comprises the use of the glazing unit according to the application, in particular of the composite glass pane of the glazing unit according to the application, in a building or in a means of transport on land, in the air or on water, preferably as glazing for a means of transport, in particular a motor vehicle. For example, the glazing unit can be used as a windscreen, a sunroof, a rear window or a side window.

[0067] In a particularly preferred embodiment, the glazing unit or the composite glass pane is a windscreen of a means of transport. Here, the functional element is preferably used as an electrically controlled sun visor, which is arranged in the upper region of the windscreen, while the majority of the windscreen does not have a functional element. The switchable region is preferably arranged substantially parallel to the upper edge of the windscreen and increases in distance from the windscreen. By means of the independently switchable switchable region, the user can determine the extent of the region adjacent to the upper edge, which will be darkened or have high light scattering, depending on the position of the sun, in order to avoid a glare effect caused by the sun.

[0068] In another preferred embodiment, the assembled glass unit or composite glass pane is a roof window of a vehicle. In this case, the functional element is preferably arranged in the entire see-through area of the composite glass pane. In one typical embodiment, this see-through area comprises the entire composite glass pane minus a surrounding edge area on at least one surface of the glass pane, in which an opaque cover print is arranged. The functional element extends across the entire see-through area, wherein its side edges are arranged in the area of the opaque cover print and are thus not visible to an observer. The switching region is preferably arranged essentially parallel to the front edge of the roof window and increases in distance from the front edge. By means of this independently switchable switching region, the user can specify which areas of the roof window should be transparent, which should be darkened or have a high light scattering, for example depending on the position of the sun, in order to avoid excessive heating of the interior space of the vehicle. It is also possible to assign each vehicle occupant, i.e. for example the driver, the front row occupants, the left and right rear row occupants, a switching region each located above them.

[0069] The application is explained in more detail with reference to the drawings and exemplary embodiments. The drawings are schematic illustrations and not to scale. The drawings do not limit the application in any way. In the drawings:

[0070] Figure 1 a top view of one embodiment of an assembled glass unit according to the application is shown,

[0071] Figure 2 a cross section through the assembled glass unit is shown, Figure 1

[0072] Figure 3 an enlarged view of the region Z in Figure 2 is shown,

[0073] Figure 4 a functional element of the assembled glass unit in Figure 1 is shown in an equivalent circuit diagram,

[0074] Figure 5 an equivalent circuit diagram of an alternative embodiment of the control unit is shown,

[0075] Figure 6 a schematic potential diagram for generating independent alternating voltages in two switching regions is shown,

[0076] Figure 7 a diagram showing exemplary independent alternating voltages in three switching regions in an embodiment according to the application, and

[0077] Figure 8 a diagram showing exemplary independent alternating voltages in three switching regions in another embodiment according to the application.

[0078] ​Figure 1 , Figure 2 , Figure 3 and Figure 4 shows one detail of an assembled glazing unit with electrically controllable optical properties according to the application, comprising a composite glass pane and a control unit 10. The composite glass pane is for example provided as a roof window glass of a passenger car, the light transmission of which can be electrically controlled locally. The composite glass pane comprises an outer glass pane 1 and an inner glass pane 2 which are connected to each other by means of an interlayer 3. The outer glass pane 1 and the inner glass pane 2 are composed of soda-lime glass, which optionally can be tinted. For example, the thickness of the outer glass pane 1 is 2.1 mm and the thickness of the inner glass pane 2 is 1.6 mm.

[0079] The interlayer 3 comprises three thermoplastic layers 3a, 3b, 3c in total, each of which is formed by a thermoplastic film made of PVB with a thickness of 0.38 mm. The first thermoplastic layer 3a is connected to the outer glass pane 1 and the second thermoplastic layer 3b is connected to the inner glass pane 2. The third thermoplastic layer 3c located therebetween has a segment in which the functional element 4 with electrically controllable optical properties is fitted substantially exactly, i.e. approximately flush on all sides. The third thermoplastic layer 3c thus forms a kind of picture frame or frame for the functional element 4 which is approximately 0.4 mm thick, which is thus encapsulated all around in thermoplastic material and is thereby protected. The functional element 4 is for example a PDLC multi-layer film which can be switched from a colourless, transparent state to a turbid, opaque (diffuse) state. The functional element 4 is a multi-layer film, consisting of an active layer 5 between two planar electrodes 8, 9 and two carrier films 6, 7. The active layer 5 contains a polymer matrix in which liquid crystals are dispersed, which align depending on the voltage applied to the planar electrodes 8, 9, whereby the optical properties can be controlled. The carrier films 6, 7 are composed of PET and have a thickness of for example 0.125 mm. The carrier films 6, 7 have an ITO coating with a thickness of approximately 100 nm facing the active layer 5, which forms the planar electrodes 8, 9. The planar electrodes 8, 9 are connected to the electrical cable 14 via a busbar (for example formed by a copper foil strip), not shown, which establishes an electrical connection to the control unit 10.

[0080] The control unit 10 is for example mounted on the inner surface of the inner glass pane 2 facing away from the interior space side of the interlayer 3. For this purpose, for example, not shown fixing elements are bonded to the inner glass pane 2, into which the control unit 10 is inserted. However, the control unit 10 does not necessarily have to be mounted directly on the composite glass pane. Alternatively, it can for example be mounted on the dashboard or the vehicle body of the vehicle, or integrated into the vehicle body electrical system of the vehicle.

[0081] The composite pane has a surrounding edge region which has an opaque cover print 13. The cover print 13 is usually made of black enamel. It is printed in a screen printing method as a printing ink with black pigments and frits and burned into the surface of the glass pane. The cover print 13 is applied, for example, on the interior space side surface of the outer pane 1 and also on the interior space side surface of the inner pane 2. The side edges of the functional element 4 are covered by the cover print 13. The control unit 10 is arranged in the opaque edge region, i.e. adhered to the cover print 13 of the inner pane 2. There, the control unit 10 does not interfere with the perspective through the composite pane and is optically inconspicuous. Furthermore, it is at a small distance from the side edges of the composite pane, so that advantageously only short cables 14 are required for the electrical connection of the functional element 14.

[0082] On the other hand, the control unit 10 is connected to the body electrical system of the vehicle, which for simplicity is not shown in Figure 1 and 2 . The control unit 10 is adapted to apply a voltage to the planar electrodes 8, 9 of the functional element 4 according to a switching signal predetermined by the driver, for example by pressing a button, which is required for the desired optical state (switching state) of the functional element 4.

[0083] The composite pane has, for example, four independent switching regions S1, S2, S3, S4, in which the switching state of the functional element 4 can be adjusted independently of one another by the control unit 10. The switching regions S1, S2, S3, S4 are arranged in succession in the direction from the front edge to the rear edge of the roof window, wherein the terms front edge and rear edge relate to the driving direction of the vehicle. By means of the switching regions S1, S2, S3, S4, the driver of the vehicle can choose, for example depending on the position of the sun, to provide only one region of the composite pane with a diffuse state instead of the entire composite pane, while the other regions remain transparent.

[0084] In order to form the switching regions S1, S2, S3, S4, the first planar electrode 8 is interrupted by three insulating lines 8', which are arranged substantially parallel to one another and extend from one side edge to the opposite side edge of the functional element 4. The insulating lines 8' are usually introduced into the first planar electrode 8 by laser machining and divide it into four materially separated electrode segments 8.1, 8.2, 8.3 and 8.4. Each electrode segment 8.1, 8.2, 8.3 and 8.4 is connected to the control unit 10 independently of one another. The control unit is adapted to apply a voltage between each electrode segment 8.1, 8.2, 8.3 and 8.4 of the first planar electrode 8 on the one hand and the second planar electrode 9 on the other hand independently of one another, so that segments of the active layer 5 located therebetween are loaded with the required voltage in order to achieve the desired switching state.

[0085] AsFigure 4 The control unit 10 is electrically connected to a DC voltage source 15 via the vehicle body of the vehicle, as shown in the equivalent circuit diagram. In the field of vehicles, the DC voltage source 15 usually provides a DC voltage of 12 to 14 V (on-board voltage of the vehicle). The control unit 10 is equipped with a DC transformer 11, which converts the on-board voltage (primary voltage) into a DC voltage having a higher magnitude, for example 65 V (secondary voltage). The secondary voltage must be sufficiently high to achieve 100% switching states of the functional element 4. The control unit 10 is also equipped with four inverters 12, which convert the secondary voltage into an AC voltage. Here, each inverter 12 is assigned to and electrically connected with exactly one electrode segment 8.1, 8.2, 8.3, 8.4 of the first planar electrode 8. The second planar electrode 9 is connected with each inverter 12.

[0086] Figure 5 An equivalent circuit diagram schematically shows an alternative embodiment of the control unit. In contrast to the embodiment shown in Fig. 1, the control unit is equipped with five inverters 12. Four inverters 12 are each assigned to and electrically connected with exactly one electrode segment 8.1, 8.2, 8.3, 8.4 of the first planar electrode 8. The second planar electrode 9 is connected with the fifth inverter 12. For the sake of simplicity, the connections to the electrode segments 8.1, 8.2, 8.3, 8.4 and to the second planar electrode 9 are indicated by arrows, the functional element 4 itself is not shown. Figure 4

[0087] With two control units 10 according to Fig. 2, it is possible to provide the different switching regions S1, S2, S3, S4 with the required mutually independent AC voltages according to the application. In this case, in particular, the reference potential applied to the second planar electrode 9 remains constant over time. The switching potentials applied to the electrode segments 8.1, 8.2, 8.3, 8.4 of the first planar electrode 8 independently of one another change over time. The magnitude and phase of each switching potential can be adjusted independently, in particular under pure software control, which can be easily implemented. The AC voltage of each switching region S1, S2, S3, S4 results as a time-varying difference between the switching potential and the constant reference potential, which changes over time. Figure 4 5

[0088] Figure 6 ​​​The potentials in the case where both switching regions S1, S2 are activated are shown by way of example, that is to say are intended to be loaded with an alternating voltage in order to produce a switching state of greater than 0%, for example 100%. To this end, the assigned electrode sections 8.1, 8.2 of the first planar electrode 8 are connected to their inverter 12 which is loaded with a switching potential which is modulated over time as a sinusoidal function. The magnitude (amplitude) of the switching potential is chosen to be the same for both electrode sections 8.1, 8.2 and is sufficiently high to produce a maximum change in the optical properties of the active layer 5 between the electrode sections 8.1, 8.2 and the second planar electrode 9 (switching state 100%). However, they are phase-shifted by 180° from one another. The reference potential applied to the unsegmented second planar electrode 9 is constant over time and is 0 V. There is then a sinusoidal alternating voltage (sinusoidal voltage) between each electrode section 8.1, 8.2 on the one hand and the second planar electrode 9 on the other hand which arises as a time-varying difference between the respective switching potential and the reference potential. The alternating voltage has the same amplitude, but is phase-shifted by 180°.

[0089] If no "real" alternating voltage with negative components is available, it is also possible to choose a value greater than 0 V for the reference potential, around which the switching potential oscillates, thereby achieving an effective alternating voltage with "relative" positive and negative contributions.

[0090] The remaining two switching regions S3, S4 are not activated, so their switching state should be 0% and thus be voltage-free. Typically, the switching is carried out such that the two relevant electrode sections 8.3, 8.4 are loaded with a switching potential which corresponds to the nominal reference potential - in this case a 0 V potential which is constant over time. This is advantageous for rapid discharge in the case where the switching regions S3, S4 were previously activated. Furthermore, it makes the structure more robust against so-called "dirt tolerance", in particular caused by dust or moisture. All switching regions S1, S2, S3, S4 form a closed circuit involving all electrode sections 8.1, 8.2, 8.3, 8.4 of the first planar electrode 8 as well as the second planar electrode 9.

[0091] If the activated switching regions S1, S2 are operated in the conventional manner with in- phase alternating voltages, a rectified current flow will be formed through the relevant part of the active layer 5 between each of the electrode sections 8.1, 8.2 and the second planar electrode 9. Since the ITO layer used as planar electrode 8, 9 has a relatively high electrical resistance, this current flow will result in a potential shift of the second planar electrode 9. The result of this is now that a certain voltage will be produced in the switching regions S3, S4 which should in fact have a voltage-free switching state of 0%, so a limited switching state of greater than 0% will be produced in the switching regions S3, S4 involved, which is in fact undesirable. In this case one speaks of a communication (CrossTalk) between the switching regions S1, S2, S3, S4.

[0092] This effect can be avoided by a phase shift of the alternating voltage of the activated switching regions S1, S2. Due to the 180° phase shift, the currents in the switching regions S1, S2 are always in opposite directions, i.e. reversed. The contribution to the potential offset of the second planar electrode 9 thus compensates each other at any point in time. In summary, the potential offset is prevented and the non-activated switching regions S3, S4 remain always voltage-free.

[0093] Even in the case of a larger even number of activated switching regions, the "cross-talk" can be ideally avoided in this way if the switching regions are divided into two groups, wherein the switching regions of the same group are operated with the same phase of the alternating voltage and the alternating voltages of the two groups have a phase shift of 180°.

[0094] Figure 7 Exemplarily, a sinusoidal voltage is shown in the case where an odd number of switching regions, i.e. three switching regions S1, S2, S3, are intended to be activated, that is, are intended to be loaded with an alternating voltage to generate a switching state of more than 0%, for example 100%. Two switching regions S1, S3 are operated with the same phase of the alternating voltage. The switching region S2 is operated with an alternating voltage having a phase shift of 180°.

[0095] The resulting reversed currents of the switching regions S1, S3 compensate each other and thus do not contribute to the potential offset of the second planar electrode 9. The current in the switching region S2 is not compensated and leads to a potential offset. However, the potential offset is significantly less pronounced compared to if all switching regions S1, S2, S3 were operated with the same phase and the rectified current were added. In this case, the potential offset and the "cross-talk" associated therewith are not completely avoided, but at least significantly reduced.

[0096] Figure 8 Exemplarily, a sinusoidal voltage is shown in the case where an odd number of switching regions, i.e. three switching regions S1, S2, S3, are intended to be activated, that is, are intended to be loaded with an alternating voltage to generate a switching state of more than 0%, for example 100%. Two switching regions S1, S3 are operated with the same phase of the alternating voltage. The switching region S2 is operated with an alternating voltage having a phase shift of 180°.

[0097] All switching regions have a phase shift of 120° or an integer multiple thereof:

[0098] - The phase shift between the switching regions S1, S2 is 120°.

[0099] - The phase shift between the switching regions S2, S3 is 120°.

[0100] - the phase shift between the switching regions S1, S3 is 240°, which in this case corresponds to a phase shift of -120° (i.e. a magnitude of 120° phase shift in the opposite direction).

[0101] By this embodiment, in which the phase shift is selected according to the number of activated switching regions, respectively, and all switching regions are operated phase-shifted to each other, an ideal compensation of the potential offset of the second planar electrode 9 can always be achieved, even in the case of an odd number of activated switching regions. Crosstalk is prevented in any case.

[0102] List of reference signs:

[0103] (S1, S2, S3, S4) independent switching regions of the glazing unit

[0104] (1 ) outer glass pane

[0105] (2) inner glass pane

[0106] (3) thermoplastic interlayer

[0107] (3a) first layer of the interlayer 3

[0108] (3b) second layer of the interlayer 3

[0109] (3c) third layer of the interlayer 3

[0110] (4) functional element with electrically controllable optical properties

[0111] (5) active layer of the functional element 4

[0112] (6) first carrier film of the functional element 4

[0113] (7) second carrier film of the functional element 4

[0114] (8) first planar electrode of the functional element 4

[0115] (8.1, 8.2, 8.3, 8.4) electrode segments of the first planar electrode 8

[0116] (8') insulating line between the two electrode segments 8.1, 8.2, 8.3, 8.4

[0117] (9) second planar electrode of the functional element 4

[0118] (10) control unit

[0119] (1 1 ) DC voltage transformer

[0120] (12) inverter

[0121] (13) cover print

[0122] (14) cable

[0123] (15) DC voltage source

[0124] XX' cross-hatching

[0125] Y enlarged area.

Claims

1. Assembled glass unit with electrically controllable optical properties with a plurality of independent switching regions (S1, S2, S3, S4), comprising - a composite glass pane, comprising - an outer glass pane (1) and an inner glass pane (2), which are connected to one another by a thermoplastic intermediate layer (3), - an electrically controllable functional element (4), which is arranged between the outer glass pane (1) and the inner glass pane (2) and has an active layer (5) with electrically controllable optical properties between a first planar electrode (8) and a second planar electrode (9), - a control unit (10), which is suitable for controlling the optical properties of the functional element (4), wherein the first planar electrode (8) is divided into at least two separate electrode sections (8.1, 8.2, 8.3, 8.4) by at least one insulating line (8’), wherein each electrode section (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) and the second planar electrode (9) are electrically connected to the control unit (10) such that an alternating voltage can be applied between each electrode section (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) and the second planar electrode (9) independently of one another in order to control the optical properties of the segment of the active layer (5) located therebetween, characterized in that the control unit (10) is suitable for applying one alternating voltage each between at least two electrode sections (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand, wherein the alternating voltages are phase-shifted.

2. The assembled glazing unit of claim 1, wherein, The functional element (4) is a PDLC functional element or a SPD functional element.

3. The assembled glazing unit of claim 1 or 2, wherein, The control unit (10) - is connected to a direct voltage source (15) with a primary voltage, - is optionally equipped with a direct voltage transformer (11), which is suitable for converting the primary voltage into a higher secondary voltage, and - is equipped with a plurality of inverters (12), which are suitable for converting the primary voltage or the secondary voltage into an alternating voltage.

4. The assembled glazing unit of claim 3, wherein, The number of inverters (12) corresponds to the number of electrode sections (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8), and wherein each inverter (12) is connected to exactly one electrode section (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and to the second planar electrode (9) on the other hand.

5. Assembled glass unit according to claim 3, wherein the number of inverters (12) is one more than the number of electrode sections (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8), and wherein each electrode section (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) and the second planar electrode (9) is connected to one own inverter (12) each.

6. The assembled glazing unit according to any one of claims 1 to 2, wherein, The alternating voltage is a sinusoidal voltage.

7. The assembled glazing unit according to any one of claims 1 to 2, wherein, The first planar electrode (8) is divided into at least three separate electrode sections (8.1, 8.2, 8.3, 8.4) by at least two insulating lines (8’).

8. The assembled glazing unit according to any one of claims 1 to 2, wherein, The planar electrodes (8, 9) are formed on the basis of indium tin oxide (ITO) or silver.

9. The assembled glazing unit according to any one of claims 1 to 2, wherein, The at least one insulating line (8’) has a width of 5 pm to 500 pm.

10. Method for controlling a glazing unit with electrically controllable optical properties having a plurality of independent switching areas (S1, S2, S3, S4), wherein the glazing unit comprises - a composite glass pane comprising - an outer glass pane (1 ) and an inner glass pane (2) which are connected to each other by a thermoplastic intermediate layer (3), - an electrically controllable functional element (4) arranged between the outer glass pane (1 ) and the inner glass pane (2) and having an active layer (5) with electrically controllable optical properties between a first planar electrode (8) and a second planar electrode (9), - a control unit (10) adapted to control the optical properties of the functional element (4), wherein the first planar electrode (8) is divided into at least two separate electrode segments (8.1, 8.2, 8.3, 8.4) by at least one insulating line (8’), wherein each electrode segment (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) and the second planar electrode (9) are electrically connected to the control unit (10) such that an alternating voltage can be applied between each electrode segment (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) and the second planar electrode (9) independently from each other to control the optical properties of the segment of the active layer (5) located therebetween, characterized in that wherein each of the alternating voltages applied between at least two electrode segments (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand is phase-shifted.

11. Method according to claim 10, wherein each of the alternating voltages applied between n electrode segments (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand is phase-shifted, wherein n is an integer number, and wherein - if n is even, an alternating voltage with a first phase is applied between n / 2 electrode segments (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand and an alternating voltage with a second phase is applied between n / 2 electrode segments (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand, and - if n is odd, an alternating voltage with a first phase is applied between (n+1) / 2 electrode segments (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand and an alternating voltage with a second phase is applied between (n-1) / 2 electrode segments (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand, and wherein the first phase and the second phase have a phase shift of 180°.

12. The method of claim 11, wherein, The alternating voltages between directly adjacent electrode segments (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) on the one hand and the second planar electrode (9) on the other hand each have a phase shift of 180°.

13. The method of claim 10, wherein, In one aspect an alternating voltage with its own phase is applied between n electrode segments (8.1, 8.2, 8.3, 8.4) of a first planar electrode (8) and, in another aspect, a second planar electrode (9), wherein n is an integer, and wherein the alternating voltages have a phase shift from each other or an integer multiple thereof.

14. The method of any one of claims 10 to 13, wherein, A time-varying switching potential is applied to each electrode segment (8.1, 8.2, 8.3, 8.4) of the first planar electrode (8) and a time-constant reference potential is applied to the second planar electrode (9) to generate an alternating voltage.

15. Use of the assembled glazing unit according to any one of claims 1 to 9 as a window pane of a vehicle.

16. Use according to claim 15, wherein the assembled glazing unit is used as a windshield or a sunroof pane.

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