EP4164879A1

EP4164879A1 - Method for electrically controlling a functional element enclosed in a glazing unit

Info

Publication number: EP4164879A1
Application number: EP21729482.6A
Authority: EP
Inventors: Richard STELZER; Bastian KLAUSS; Michael Zeiss; Doane Shelby Craig
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2020-06-16
Filing date: 2021-05-27
Publication date: 2023-04-19
Also published as: CN114144245A; WO2021254761A1; US20230219325A1

Abstract

The invention relates to a method for electrically controlling at least one functional element (2) with electrically controllable optical properties enclosed in a glazing unit (1), wherein the optical properties are controlled by a control unit (11), wherein the control unit (11) is connected to at least two transparent flat electrodes (10) of the functional element (2), an electrical voltage is applied by the control unit (11) between the flat electrodes (10) and the polarity of the voltage is periodically changed, wherein the voltage has a trapezoidal curve and wherein, by means of the control unit (11), a) an increasing electrical voltage is applied to charge the functional element (2), wherein the electrical voltage increases to a first peak value, b) the electrical voltage is reduced from the first peak value to a final voltage to discharge the functional element (2), c) the functional element (2) is charged with the increasing electrical voltage with the opposite polarity to step a), wherein the electrical voltage increases to a second peak value, d) the electrical voltage is reduced from the second peak value to the final voltage to discharge the functional element, and the steps a) to d) are periodically repeated, and wherein, in step b) and/or step d), electrical energy is transferred from the functional element (2) to the control unit (11), and the control unit (11) has means for temporarily storing energy output by the functional element (2).

Description

l

Method for the electrical control of a functional element stored in a glazing unit

The invention relates to a method for controlling a functional element stored in a glazing unit, a glazing arrangement and a use of the glazing arrangement.

Functional elements with electrically controllable optical properties are used in the industrial production of glazing units. Such glazing units are often composite panes in which a functional element is embedded. The composite panes consist of at least one outer pane, one inner pane and an adhesive intermediate layer that connects the outer pane with the inner pane over a large area. Typical intermediate layers are polyvinyl butyral films which, in addition to their adhesive properties, have high toughness and high acoustic damping. The intermediate layer prevents the laminated glass pane from disintegrating in the event of damage. The composite pane only gets cracks, but remains dimensionally stable.

Composite panes with electrically controllable optical properties are known from the prior art. Such composite panes contain a functional element which typically contains an active layer between two surface electrodes. The optical properties of the active layer can be changed by a voltage applied to the surface electrodes. An example of this are electrochromic functional elements, which are known, for example, from US 20120026573 A1 and WO 2012007334 A1. Another example are SPD (Suspended Particle Device) or PDLC (Polymer Dispersed Liquid Crystal) functional elements, which are known, for example, from EP 0876608 B1 and WO 2011033313 A1. The applied voltage can be used to control the transmission of visible light through electrochromic or SPD / PDLC functional elements.

SPD and PDLC functional elements are commercially available as multilayer films. The flat electrodes required to apply a voltage are arranged between two PET carrier films. During the manufacture of the glazing unit, the functional element is made from the multilayer film in the desired size and shape cut out and inserted between the foils of an intermediate layer. The flat electrodes are connected in an electrically conductive manner to a control module (ECU) via flat conductors outside the composite pane. The control module is intended to apply an electrical voltage between the surface electrodes.

US 2017/0090224 A discloses a laminated vehicle glazing with a PDLC film, which is operated electrically with alternating current. The electrical alternating voltage is not sinusoidal, whereby an effective voltage of 80 V _{eff is} not exceeded.

The machine translation of JP 2013072895 (A) appears to disclose a dimmer for a liquid crystal unit.

US 2020/0133042 A1 discloses a device with a functional element with electrically controllable optical properties. The device comprises an electrical energy source with an output voltage, the functional element and two electrical leads that connect the functional element to the energy source, the output voltage being an alternating voltage with a frequency of 40 Hz to 210 Hz, a maximum amplitude U _max of 24 V to 100 V and a slope in the output voltage range between -80% and 80% U _max from 0.05 * U _max / 100 ps to 0.1 * U _max / 100 ps and in the output voltage U range between 80% and -80% from -0.05 * U _max / 100 ps to -0.1 * U _max / 100 ps.

Windshields have been proposed in which an electrically controllable sun visor is implemented by means of a functional element in order to replace the mechanical foldable sun visor in motor vehicles.

Although functional elements of this type respond quickly to a change in the applied voltage, the apparent power required to control them is relatively high due to the mainly capacitive behavior, in particular in comparison to the active power consumed. The object of the present invention is to provide a method which uses the energy consumption of a functional element stored in a glazing unit as effectively as possible.

The object of the present invention is achieved according to the invention by a method according to independent claim 1. Preferred embodiments of the invention emerge from the subclaims.

The method according to the invention for electrically controlling at least one functional element embedded in a glazing unit with electrically controllable optical properties comprises at least the following steps:

• Control of the optical properties by means of a control unit, the control unit being connected to at least two transparent surface electrodes of the functional element,

• Application of an electrical voltage between the surface electrodes by means of the control unit and a periodic change in the polarity of the voltage, the voltage having a trapezoidal profile.

With the trapezoidal course of the voltage over time, the reduction of the voltage from the peak value is used to advantage. In order to lengthen the discharge phase of the surface electrodes, the voltage is gradually reduced so that the surface electrodes are discharged with a delay.

In the context of the invention, a profile with moderate edge steepnesses, an approximately trapezoidal profile and / or a profile of a continuously differentiable function can be considered as trapezoidal. The electrical energy discharged in the process can advantageously be captured and stored. In contrast to conventional methods, the reactive power, which is otherwise lost in the form of thermal energy, is advantageously temporarily stored and reused. By means of the control unit a) an increasing electrical voltage can be applied to charge the functional element, the electrical voltage rising up to a first peak value, b) the electrical voltage can be reduced from the first peak value to a final voltage for discharging the functional element, c) the Functional element with reverse polarity as in step a) are charged with an increasing electrical voltage, the electrical voltage rising up to a second peak value, d) the electrical voltage being reduced from the second peak value to the final voltage for discharging the functional element, and the method steps a) to process step d) are repeated periodically.

Furthermore, in method step b) and / or in step d), electrical energy can be transmitted from the functional element to the control unit. The control unit can have means for temporarily storing the electrical energy output by the functional module, for example an intermediate storage device. This energy can be temporarily stored in the intermediate store. This energy can be used the next time the functional element is charged. For example, in method step a) and / or method step c), the temporarily stored energy can be used to charge the functional element.

The control unit can have a capacity as a buffer store, which stores the energy transmitted by the functional module. This has the advantage that conventional components can be used.

The control unit also includes means, in particular a half-bridge circuit. The half-bridge circuit is intended to convert the energy withdrawn from the functional element in such a way that this energy can be stored in the intermediate storage device.

Furthermore, the control unit can have an LC filter and an output transistor (IGBT, FET or thyristor). Furthermore, the control unit can have an inductance, in particular a coil, which is electrically connected to a connection to one of the surface electrodes and a second connection, the inductance is connected to an input of a switch, in particular a transistor. Another advantage is the fact that the control strategy uses pulse width modulation. The electrical voltage can be changed by means of pulse width modulation. On the basis of these properties it can be determined that the method offers an efficient solution for controlling the applied electrical voltage.

In a preferred embodiment, the increasing voltage can be applied for the same period of time as the period of time during which the voltage is reduced to the final voltage. This results in a symmetrical course of the electrical voltage on the surface electrodes. Furthermore, the first peak value of the voltage can have a value of 48 V, for example, the end voltage being 0 V. The period of the voltage can correspond to a frequency of approx. 50 Hz.

The glazing unit comprises at least one outer pane and one inner pane, which are connected to one another via a thermoplastic intermediate layer. The functional element is embedded in the thermoplastic intermediate layer. The glazing unit is provided for separating the interior space from the external environment in a window opening, for example of a vehicle, a building or a room. In the context of the invention, the inner pane is used to denote the pane facing the interior. The outer pane is referred to as the pane facing the external environment. The thermoplastic intermediate layer is used to connect the two panes.

The thermoplastic intermediate layer contains at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) or polyurethane (PU) or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The intermediate layer is typically formed from a thermoplastic film. The thickness of the intermediate layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm.

The outer pane and the inner pane are preferably made of glass, in particular soda-lime glass, which is common for window panes. In principle, however, the panes can also be made of other types of glass (for example borosilicate glass, quartz glass, aluminosilicate glass) or transparent plastics (for example polymethyl methacrylate or polycarbonate). The thickness of the outer pane and the inner pane can vary widely. Discs with a thickness in the range from 0.8 mm to 5 mm, preferably from 1.4 mm to 2.5 mm, for example those with the standard thicknesses of 1.6 mm or 2.1 mm, are preferably used.

The outer pane, the inner pane and the thermoplastic intermediate layer can be clear and colorless, but also tinted or colored. A corresponding windshield must have sufficient light transmission in the central viewing area, preferably at least 70% in the main viewing area A in accordance with ECE-R43. The outer pane and the inner panes can not be preloaded, partially preloaded or preloaded independently of one another. If at least one of the disks is to have a pre-tension, this can be a thermal or chemical pre-tension.

The outer pane, the inner pane and / or the intermediate layer can have further suitable coatings known per se, for example anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sun protection coatings or low-E coatings.

The glazing unit can be manufactured by methods known per se. The outer pane and the inner pane are laminated to one another via the intermediate layer, for example by autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators or combinations thereof. The connection of the outer pane and the inner pane usually takes place under the action of heat, vacuum and / or pressure.

The glazing unit comprises a functional element with electrically controllable optical properties that is embedded in the intermediate layer. The functional element is typically arranged between at least two layers of thermoplastic material of the intermediate layer, it being connected to the outer pane by the first layer and to the inner pane by the second layer. Such a functional element comprises at least one active layer which is arranged between a first carrier film and a second carrier film. The active layer has variable optical properties that can be controlled by an electrical voltage applied to the active layer. Electrically controllable optical properties are understood in the context of the invention to be those properties that are continuously controllable, but equally also those that can be switched between two or more discrete states. The optical properties relate in particular to the light transmission and / or the scattering behavior. The functional element also comprises flat electrodes for applying the voltage to the active layer, which are preferably arranged between the carrier films and the active layer.

In an advantageous embodiment, the functional element is a PDLC functional element, in particular one that switches at least one area of the glazing unit from a transparent to an opaque state and vice versa. The active layer of a PDLC functional element contains liquid crystals which are embedded in a polymer matrix. In a further preferred embodiment, the functional element is an SPD functional element. The active layer contains suspended particles, and the absorption of light by the active layer can be changed by applying a voltage to the surface electrodes.

The surface electrodes and the active layer are arranged essentially parallel to the surfaces of the outer pane and the inner pane. The surface electrodes are connected to an external voltage source. The electrical contacting, as well as the connection to the energy source of the active layer, is realized by suitable connecting cables, for example flat conductors or foil conductors, which are optionally connected to the flat electrodes via so-called bus bars, for example strips of an electrically conductive material or electrically conductive prints are connected.

The thickness of the functional element is, for example, from 0.4 mm to 1 mm.

The flat electrodes are preferably designed as transparent, electrically conductive layers. The surface electrodes preferably contain at least one metal, a metal alloy or a transparent conductive oxide (transparent conducting oxide, TCO). The surface electrodes can, for example, silver, gold, copper, nickel, chromium, tungsten, indium tin oxide (ITO), gallium-doped or aluminum-doped zinc oxide and / or fluorine contain doped or antimony-doped tin oxide. The surface electrodes preferably have a thickness of 10 nm (nanometers) to 2 μm (micrometers), particularly preferably 20 nm to 1 μm, very particularly preferably 30 nm to 500 nm.

The invention also comprises a glazing arrangement of a vehicle or building, at least comprising a glazing unit with electrically controllable optical properties. The glazing unit comprises the outer pane and the inner pane, which are connected to one another via a thermoplastic intermediate layer and in which a functional element with electrically controllable optical properties is embedded. The functional element has an active layer to which transparent flat electrodes are assigned on both surfaces. Furthermore, the glazing arrangement comprises a control unit for electrically controlling the optical properties of the glazing unit according to the method according to the invention, which is connected to the surface electrodes of the functional element and is designed to apply an electrical voltage between the surface electrodes. The control unit is provided for periodically changing the polarity of the voltage, the voltage having a trapezoidal profile. According to the invention, the control unit has means for the effective use of electrical energy.

According to a further aspect of the invention, a vehicle, in particular a car, with the glazing arrangement according to the invention is described.

A further aspect of the invention comprises the use of the glazing arrangement according to the invention in means of transport for traffic on land, in the air or on water, in particular in motor vehicles, for example as a windshield, rear window, side window and / or roof window and as a functional individual piece, and as a built-in part in Furniture, appliances and buildings. The invention is explained in more detail below with reference to figures and exemplary embodiments. The figures are a schematic representation and are not true to scale. The figures do not restrict the invention in any way.

Show it:

1 shows a schematic representation of a glazing arrangement, FIG. 2 shows a cross-sectional representation of a first thermoplastic layer with a functional element with an electrical connection,

FIG. 3 shows a graphic representation of a course of an electrical voltage applied to the functional element according to the method according to the invention,

FIG. 4 shows a switching device for implementing the method according to the invention, FIG. 5 an exemplary embodiment of a switching device for operating the functional element according to the method,

FIG. 6 shows a profile of a voltage VPDL _C I and profile of a voltage VPDL _C 2, FIG. 7 shows a profile of a voltage VPDLC, and FIG. 8 shows an equivalent circuit diagram of the functional element.

In the exemplary embodiments, the described components each represent features of the invention that are to be considered independently of one another and which are also to be regarded as part of the invention individually or in a combination other than the one shown.

Figures with numerical values are generally not to be understood as exact values, but also include a tolerance of +/- 1% up to +/- 10%.

FIG. 1 shows a schematic representation of a glazing arrangement 100 with a glazing unit 1, which can be installed, for example, in a motor vehicle or in a building. The glazing unit 1 comprises an outer pane 1 a and an inner pane 1 b, which are connected to one another via an intermediate layer 3. the ok

Outer pane 1a has a thickness of 2.1 mm and consists of a soda-lime glass. The inner pane 1b has a thickness of 1.6 mm and consists of a clear soda-lime glass.

The glazing unit 1 is equipped in a central area with the functional element 2, which is embedded in the intermediate layer 3. The intermediate layer 3 comprises a total of three thermoplastic layers, each of which is formed by a thermoplastic film with a thickness of 0.38 mm made of PVB. The first thermoplastic layer 3a is connected to the outer pane 1, the second thermoplastic layer 3b to the inner pane 1b. The intervening third thermoplastic layer surrounds the cut functional element 2 (PDLC multilayer film) essentially flush on all sides. The functional element 2 is thus embedded all around in thermoplastic material and thus protected.

Figure 1 also shows the switched-on state of the glazing arrangement 100 with the functional element 2 stored in the glazing unit 1. The glazing arrangement 100 also includes a control unit 11 (also called ECU in a motor vehicle), which is electrically connected to the functional element 2 via a closed switch 12, a flat conductor , electrical connections 13 (Figure 2) and busbar 8 is connected so that an electrical voltage VPDLC can be applied to the connections 13.

The optical properties of the glazing unit 1 are controlled by means of the control unit 11. For this purpose, control unit 11 is electrically connected to two transparent surface electrodes 10 of functional element 2. An electrical voltage VPDL _C is applied between the surface electrodes 10 by means of the control unit 11 and the polarity of the voltage VPDL _{C is changed} periodically (alternately). The voltage VPDL _C has a trapezoidal profile, according to FIG. 3.

FIG. 2 shows a cross-sectional view of a first thermoplastic layer 3a with a functional element 2 with an electrical connection 13. In this embodiment, the first thermoplastic layer 3a is a PVB film with a thickness of 0.38 mm. ll

The functional element 2 is a multilayer film which is composed of an active layer 9, two surface electrodes 10 and two carrier films 11. Such multilayer films are commercially available as PDLC multilayer films. The active layer 9 is arranged between the two surface electrodes 10. The active layer 9 contains a polymer matrix with liquid crystals dispersed therein, which align themselves as a function of the electrical voltage applied to the surface electrodes 10, whereby the optical properties can be controlled. The carrier films 11 are made of PET and have a thickness of approximately 0.125 mm. The carrier foils 11 are provided with a coating of ITO facing the active layer 9 with a thickness of approximately 100 nm, which form the surface electrodes 10.

The surface electrodes 10 can be connected to an electrical voltage via electrically conductive busbars 8. The busbars 8 are formed here by a silver-containing screen printing. Alternatively, the bus bars can be formed by electrically conductive metal strips or an electrically conductive coating. Metal (copper) here includes metal alloy (copper alloy). A bus bar 8 is connected to the surface electrode 10 by the carrier film 11, a surface electrode 10 and the active layer being cut out along an edge region of the respective side of the functional element 2 so that the other, opposite surface electrode 10 with the associated carrier film 11 protrudes. The respective bus bar 8 is arranged on the protruding surface electrode 10.

Two conductor wires connect the busbars 8 via a flat conductor each with an electrical voltage VPDLC. In this case, a conductor wire is connected in an electrically conductive manner to a respective connection area of the flat conductor. In addition, an electrically conductive connection between a respective conductor wire and a connection area 13 can be reinforced by a soldered connection.

FIG. 3 shows a graphic representation of a profile of an electrical voltage VPDLC applied to the functional element 2. In this example, the voltage VPDLC was applied to the functional element 2.

The applied electrical voltage V _PDLC is an alternating voltage. The control unit 11 generates the voltage V _PDLC with a trapezoidal profile. The frequency of the voltage is preferably 50 Hz with an effective voltage of 48 V. The trapezoidal shape has a falling slope of approx. 5% of the period duration, marked in FIG. 3, in order to lengthen the discharge phase of the functional element. The voltage curve shown in Figure 3 was applied to the functional element 2 as follows: a) an increasing electrical voltage to charge the functional element 2, the electrical voltage rising to a first peak value, b) the electrical voltage was increased to a final voltage of 0 V. to discharge the functional element 2, c) the functional element 2 was charged with the opposite polarity as in step a) with an increasing electrical voltage, the electrical voltage rising to a second peak value, d) the electrical voltage was reduced from to the final voltage of 0 V is reduced to discharge the functional element 2, and steps a) to step d) are repeated periodically.

FIG. 4 shows a circuit diagram of an embodiment of a first half bridge with a downstream LC filter (L1, C2) at the time the functional element 2 is discharged. To operate the functional element, a further, second half bridge shown in FIG. 5 is necessary.

By means of the LC filter (L1, C2) and a pulse width modulation PWM, the flat electrodes 10 are immediately discharged with a delay when the polarity is switched. The pulse duty factor of the PWM is decisive for the discharge time. For this purpose, an inductance, for example coil L1, is provided in control unit 11. The coil L1 is connected to a connection to a surface electrode 10. With its second connection, the coil L1 is connected to one input each of a switch, e.g. a transistor (FET, thyristor or MOSFET), Q1 and Q2. The output of transistor Q1 is connected to ground. The output of transistor Q2 is connected to a first terminal of a capacitor C1 as a capacitance. The voltage Vgs between the gate and source of the transistor is 0V. The transistor Q1 can be switched to an electrically conductive state by means of the pulse width modulation PWM. A second connection of the capacitor C1 is connected to ground. The capacitor C1 serves as a buffer. A capacitor C2 capacitively connects the surface electrode 10 to the ground potential. The circuit shown in FIG. 4 can be operated as a half bridge with an LC filter.

To switch on transparency in the glazing unit 1, the control unit 11 generates the electrical voltage VPDL _C at the electrical connection 13. The control unit 11 can generate the electrical voltage VPDL _C as an alternating voltage with a trapezoidal profile, as shown by way of example in FIG. After the functional element 2 has been charged to 48 V, the transistor Q1 is switched with a PWM signal. While transistor Q1 switches, a current flows from functional element 2 (PDLC) via coil L1 and transistor Q1 to potential GND (ground potential).

As soon as the transistor Q1 is switched off and no current can flow through the transistor Q1, the coil L1 counteracts this, so that the current continues to flow through the transistor Q2 into a capacitor C1. This increases the voltage on capacitor C1. The energy stored in the capacitor C1 can be used as additional electrical energy for the next charging of the functional element 2 and will not dissipate as reactive power in the form of thermal energy, as is the case with a conventional controller. This result was unexpected and surprising for the person skilled in the art.

FIG. 5 shows a switching device for operating the functional element 2. The switching device comprises the first half-bridge, shown in FIG. 4, consisting of transistor Q11 and transistor Q21 with a downstream LC filter L11, C21 and a second half-bridge. The second half bridge comprises transistor Q12 and transistor Q22 with a downstream LC filter L12, C22. Analogously to FIG. 4, the transistor Q11 is switched to an electrically conductive state by means of PWM1.

The generation of the voltage VPDLC applied to the functional element 2, in particular alternating voltage, takes place via the two half bridges, which switch anticyclically between 0V and an intermediate circuit voltage Vci. The intermediate circuit voltage Vci is applied to the capacitor C1. The negative voltage "sees" only the functional element 2, since this is connected between the two outputs of the two half bridges.

The state shown in FIG. 4 (Vgs = 0V at Q2, PWM at Q1) only applies to the falling edge of the respective half-bridge.

FIGS. 6 to 8 illustrate the generation of the electrical voltage VPDLC applied to the functional element 2. FIG. 6 shows a profile of a voltage VPDLCI which is present at the output of the first half bridge, as shown in FIG. Furthermore, in Figure 6 is the The course of a voltage V _PDLC 2, which is present at the output of the second half-bridge, is shown. Both the voltage V _PDLCI and the voltage V _PDLC 2 have a trapezoidal shape. In FIG. 7, a voltage difference between the voltages V _PDLCI and V _PDLC 2 is shown as the voltage V _PDLC . FIG. 8 shows an equivalent circuit diagram of the functional element 2. The functional element 2 represents a capacitance CPDLC, to which the electrical voltage VPDLC is applied as the difference between the voltages VPDLCI and VPDLC2.

List of reference symbols:

1 glazing unit

1a outer pane

1b inner pane

2 functional element

3 intermediate layer

3a first thermoplastic layer

3b second thermoplastic layer

7 carrier film

8 busbars

9 active layer

10 surface electrodes 11 control unit 12 switch 13 electrical connection

100 glazing arrangement

C1 capacitor

C2, C21, C22 capacitor D1 diode

L1, L11, L12 coil Q1, Q11, Q12 transistor Q2, Q21, Q22 transistor

VpDLC, VpDLCI, VpDLC2 electrical voltage

Claims

1. A method for the electrical control of at least one functional element (2) embedded in a glazing unit (1) with electrically controllable optical properties, wherein,

• the optical properties are controlled by means of a control unit (11), the control unit (11) being connected to at least two transparent surface electrodes (10) of the functional element (2),

• an electrical voltage is applied between the surface electrodes (10) by means of the control unit (11) and the polarity of the voltage is changed periodically, the voltage having a trapezoidal curve, and where by means of the control unit (11) a) an increasing electrical voltage for Charging of the functional element (2) is applied, the electrical voltage rising up to a first peak value, b) the electrical voltage is reduced from the first peak value to a final voltage for discharging the functional element (2), c) the functional element (2) with reverse polarity as in step a) is charged with the increasing electrical voltage, the electrical voltage rising up to a second peak value, d) the electrical voltage is reduced from the second peak value to the final voltage for discharging the functional element, and steps a) to be repeated periodically up to step d), and where in step b) and / or in step d) electrical energy from the functional element

(2) is transmitted to the control unit (11) and the control unit

(11) Means for temporarily storing an output from the functional element (2)

Having energy.

2. The method according to claim 1, wherein the electrical voltage by means of a

Pulse width modulation is changeable.

3. The method according to any one of the preceding claims, in which, in particular in step a) and / or step c), energy temporarily stored in the control unit (11) is used to charge the functional element (2).

4. The method according to any one of the preceding claims, wherein the

Control unit (11) has a capacity (C1) for the intermediate storage of energy transmitted by the functional module (2).

5. The method according to any one of the preceding claims, wherein the

Control unit (11) has an LC filter and an output transistor (Q1), in particular FET or thyristor.

6. The method according to any one of the preceding claims, wherein the

Control unit (11) has an inductance (L1) which is electrically connected to a connection to a surface electrode (10) and a second connection, the inductance (L1) is connected to an input of a switch, in particular a transistor (Q1).

7. The method according to any one of the preceding claims, wherein the

Glazing unit (1), an outer pane (1a) and an inner pane (2b) which are connected to one another via a thermoplastic intermediate layer (3) and in which the functional element (2) is embedded.

8. The method according to any one of the preceding claims, wherein the functional element (2) is a PDLC functional element which makes the glazing unit (1) appear transparent at least in areas when the power supply is switched on and opaque when the power supply is switched off.

9. The method according to any one of claims 1 to 8, wherein the increasing voltage is applied for the same period of time as the period of time during which the voltage is reduced to the final voltage.

10. The method according to any one of claims 1 to 9, wherein the first peak value corresponds to the voltage of 48 V and / or the end voltage is 0 V.

11. Glazing arrangement (100) of a vehicle or building, at least comprising

• a glazing unit (1) with electrically controllable optical properties, which comprises an outer pane (1a) and an inner pane (1b) which are connected to one another via a thermoplastic intermediate layer (3), and in which a functional element (2) with electrically controllable optical Properties is incorporated, comprising an active layer (9) to which transparent surface electrodes (10) are assigned on both surfaces, and

• a control unit (11) for the electrical control of the optical properties of the glazing unit according to a method according to one of the preceding claims 1 to 10.

12. A vehicle, in particular a car, with a glazing arrangement according to claim 11.

13. Use of the glazing arrangement according to claim 11 in means of transport for traffic, in the air or on water, in particular in motor vehicles, for example as a windshield, rear window, side window and / or roof window and as a functional individual item, and as a built-in part in furniture, devices and buildings.