Method for controlling a glass unit with electrically controllable optical properties

Abstract

The invention relates to a method for electrically controlling at least one functional element (2) with electrically controllable optical properties in a glass unit (100) in which • the glass unit (100) comprises a composite pane (1) with an outer pane (1a) and an inner pane (1b), which are connected to one another via a thermoplastic intermediate layer (3, 3a, 3b), • the functional element (2) is arranged between the outer pane (1a) and the inner pane (1b) and has an active layer (9) with electrically controllable optical properties between a first planar electrode (10) and a second planar electrode (10), • the optical properties are controlled by means of a control unit (11), wherein the control unit (11) is connected to at least two transparent planar electrodes (10) of the functional element (2), • a voltage is applied between the planar electrodes (10) by means of the control unit (11), wherein an inverse function (300, 300') is used for determining the value of the voltage, wherein the inverse function (300, 300') is used as a linearization function in relation to the temperature, and the temperature of the functional element (2) or of the composite pane (1) is detected by means of a temperature sensor (4), is transmitted to the control unit (11), and the value of the voltage between the planar electrodes (10) is determined and applied by means of the control unit (11) as a function of the temperature of the functional element (2) or of the composite pane (1).

Description

Method for controlling glass units with electrically controllable optical properties Technical Field

[0001] The present invention relates to a method for controlling a glass unit having electrically controllable optical properties, the glass unit, and the use of the glass unit. Background Technology

[0002] Functional elements with electrically controllable optical properties are used in the industrial production of glass units. These glass units are often composite panels into which the functional elements are embedded. The composite panel consists of at least one outer panel, an inner panel, and an adhesive interlayer that connects the outer and inner panels planarly. A typical interlayer here is a polyvinyl butyral film, which, in addition to its adhesive properties, also possesses high toughness and high acoustic damping. The interlayer prevents the composite glass panel from disintegrating upon damage. The composite panel only develops cracks but maintains its shape stability.

[0003] Composite plates with electrically controllable optical properties are known from the prior art. Such composite plates contain functional elements, typically comprising an active layer between two planar electrodes. Optical properties, particularly the transmission of visible light through the active layer, can be altered by a voltage applied to the planar electrodes. An example of this is an electrochromic functional element, known for example from US 20120026573 A1 and WO 2012007334 A1. Another example is an SPD (Suspended Particle Device) functional element or a PDLC (Polymer Dispensed Liquid Crystal) functional element, known for example from EP0876608 B1 and WO 2011033313 A1. The transmission of visible light through the electrochromic or SPD / PDLC functional element can be controlled by the applied voltage.

[0004] SPD and PDLC functional elements are commercially available as multilayer films. Planar electrodes required for applying voltage are arranged between two PET carrier films. During glass cell fabrication, the functional elements are cut from the multilayer films to the desired size and shape and placed between the interlayer films. The planar electrodes are electrically connected to a control module (ECU) outside the composite plate via flat conductors. The control module is configured to apply voltage between the planar electrodes.

[0005] A windshield has been proposed, in which an electrically controllable sun visor is realized through functional elements, in order to replace the mechanically foldable sun visor in motor vehicles.

[0006] WO2019 / 011891 A1 discloses an apparatus for operating a functional element having electrically controllable optical characteristics.

[0007] However, glass units with such functional elements exhibit a temperature dependence on their transmission or even transparency. In many cases, switchable functional elements have characteristic curves that deviate significantly from a straight line and make reproducible switching behavior (Schaltverhalten) difficult. Summary of the Invention

[0008] The objective of this invention is to provide an improved method in which the behavior of transparency switching is improved.

[0009] According to the invention, the objective is achieved by a method for electrically controlling at least one functional element embedded in a glass unit, which has electrically controllable optical properties. Preferred embodiments of the invention are known from other design options.

[0010] According to the present invention, a method for electrically controlling at least one functional element in a liner glass unit having electrically controllable optical properties includes the glass unit. The glass unit includes a composite plate having an outer plate and an inner plate. The outer plate and the inner plate are interconnected via a thermoplastic interlayer. The functional element is disposed between the outer plate and the inner plate, and has an active layer with electrically controllable optical properties between a first planar electrode and a second planar electrode. The optical properties are controlled by means of a control unit, wherein the control unit is connected to at least two transparent planar electrodes of the functional element. A voltage is applied between the planar electrodes by means of the control unit.

[0011] An inverse function is used to determine the voltage value, whereby the inverse function is used as a temperature-dependent linearization function. Here, the temperature of the functional element is detected by a temperature sensor and transmitted to the control unit. The control unit determines the voltage value based on the temperature of the functional element and applies it between the planar electrodes.

[0012] The present invention is based on the understanding that the switching behavior of electrically switchable functional elements is temperature-dependent. Higher temperatures of the functional element or composite plate result in more pronounced changes in optical properties, particularly transparency, due to the voltage applied to the planar electrodes. If an inverse function is used as a temperature-dependent linearization function, the nonlinear calibration function can be linearized. In other words, the linearization function is the inverse function of the calibration function, especially the temperature-dependent calibration function. Therefore, if the inverse function is used as a temperature-dependent linearization function, the switching state can be precisely adjusted at a given temperature.

[0013] According to the invention, the temperature of the functional element or composite plate is determined so that the voltage to be applied is adapted to that temperature. It is assumed here that the composite plate has a uniform temperature overall, i.e., the temperature of the functional element is consistent with the temperature of other areas of the composite plate, which is typically, at least approximately, the case. The determination of the temperature of the composite plate therefore corresponds at least approximately to the determination of the temperature of the functional element.

[0014] The glass unit, especially the composite panel, is preferably equipped with a temperature sensor. The temperature sensor is connected to a control unit, allowing the control unit to determine the temperature of the composite panel using the sensor. The measurement signal from the temperature sensor is thus transmitted to and evaluated by the control unit, enabling the control unit to determine the temperature of the composite panel using the sensor. The temperature sensor can be integrated into the composite panel, such that it is embedded in an intermediate layer. Alternatively, the temperature sensor can be externally fastened to the composite panel or distributed to it. Here, the temperature sensor is preferably fastened to the inner panel. The temperature sensor can also be arranged in the control unit itself or in a fastening element, which the control unit uses to fasten it to the composite panel. In principle, a temperature sensor that measures temperature remotely without being directly fastened to or integrated into the composite panel, such as an IR sensor (infrared sensor), can also be used. This temperature sensor is arranged in the environment of the composite panel and aligned with it. The temperature of the functional element or the composite panel can be from 30°C to 80°C, particularly in the range of 40°C to 60°C.

[0015] In one advantageous design, the temperature sensor is arranged in a glass unit on a flat conductor or flexible circuit board.

[0016] In another advantageous design, the temperature sensor is a temperature-dependent resistor. A PTC resistor or PTC thermistor is preferably used as the temperature sensor. Platinum resistance thermometers, such as Pt100, are particularly preferred for temperature measurement.

[0017] In another advantageous design, a temperature sensor is spatially allocated to the functional element and detects the actual temperature of the functional element. Here, the temperature sensor is arranged and configured such that it can detect the temperature of the functional element. The temperature sensor can preferably be applied at the functional element. By arranging the temperature sensor at the functional element, not only can the actual temperature of the functional element be directly detected, but the manufacturing of the glass unit can also be simplified. In principle, the temperature sensor can be placed at any location within the glass unit.

[0018] Preferably, the transparency value of the functional element is determined based on the temperature of the functional element.

[0019] The planar electrode is preferably configured as a transparent conductive layer. The planar electrode preferably comprises at least one metal, metal alloy, or transparent conducting oxide (TCO). The planar electrode may, for example, comprise 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. The planar electrode preferably has a thickness of 10 nm to 2 μm, particularly preferably 20 nm to 1 μm, and entirely particularly preferably 30 nm to 500 nm. The planar electrode is preferably constructed without insulating wires. Here, the planar electrode can be constructed as a single surface. Thus, the planar electrode does not have segmented or partitioned sections.

[0020] The present invention further includes a glass unit. This glass unit comprises a composite panel consisting of at least one outer panel and an inner panel, the outer and inner panels being interconnected via a thermoplastic interlayer. Functional elements are nested within the thermoplastic interlayer. The glass unit is configured to separate an interior space from the external environment in a window opening, such as in a vehicle, building, or room. In the context of this invention, the inner panel represents the panel facing the interior space. The outer panel represents the panel facing the external environment. The thermoplastic interlayer serves to connect the two panels.

[0021] The glass unit and method are introduced together, and the description and preferred design schemes also relate to the glass unit and method. If preferred features are described in conjunction with the method, it is concluded that the glass unit is also preferably designed and applicable accordingly. Conversely, if preferred features are described in conjunction with the glass unit, it is concluded that the method is also preferably performed accordingly.

[0022] The thermoplastic interlayer comprises at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or a mixture, copolymer, or derivative thereof, particularly preferably PVB. The interlayer is typically constructed of a thermoplastic film. The thickness of the interlayer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm.

[0023] The outer and inner panels are preferably made of glass, especially soda-lime glass, which is common for window panels. However, in principle, the panels can also be made of other types of glass (e.g., borosilicate glass, quartz glass, aluminosilicate glass) or transparent plastics (e.g., polymethyl methacrylate or polycarbonate). The thickness of the outer and inner panels can vary widely. Preferably, panels with a thickness in the range of 0.8 mm to 5 mm, preferably 1.4 mm to 2.5 mm, such as panels with a standard thickness of 1.6 mm or 2.1 mm are used.

[0024] The outer, inner, and thermoplastic interlayers can be clear and colorless, but can also be colored or stained. The corresponding glass units serving as windbreaks must have sufficient light transmittance in the central field of view, preferably at least 70% in the main perspective area A according to ECE-R43. The outer and inner panels can be unstressed, partially prestressed, or prestressed, independent of each other. If at least one of the panels should be prestressed, this can be thermal or chemical prestressing.

[0025] The outer panel, inner panel, and / or intermediate layer may have other suitable coatings known per se, such as anti-reflective coatings, anti-stick coatings, scratch-resistant coatings, photocatalytic coatings, shading coatings, or low-emissivity coatings.

[0026] For example, the outer and inner panels are laminated together via an intermediate layer using methods such as autoclaving, vacuum bagging, vacuum ringing, calendering, vacuum lamination, or combinations thereof. Here, the outer and inner panels are typically joined under the influence of heat, vacuum, and / or pressure.

[0027] The glass unit includes functional elements with electrically controllable optical properties, which are embedded in an intermediate layer. The functional elements are typically arranged between at least two layers of thermoplastic material in the intermediate layer, wherein the functional elements are connected to an outer panel via a first layer and to an inner panel via a second layer.

[0028] This functional element includes at least an active layer disposed between a first carrier film and a second carrier film. The active layer has variable optical properties that can be controlled by a voltage applied to it. In the context of this invention, electrically controllable optical properties are understood as properties that can be continuously controlled, but also as properties that can be switched between two or more discrete states. The optical properties particularly relate to transparency (referred to as transmission or light transmission) and / or scattering behavior. The functional element further includes planar electrodes for applying a voltage to the active layer, preferably disposed between the carrier film and the active layer.

[0029] In an advantageous design, the functional element is a PDLC functional element, particularly one that switches at least one region of the glass cell from a transparent state to an opaque state and vice versa. The active layer of the PDLC functional element comprises liquid crystal embedded in a polymer matrix. In another preferred design, the functional element is an SPD functional element. Here, the active layer comprises suspended particles, wherein the absorption of light through the active layer can be altered by applying a voltage to a planar electrode.

[0030] The planar electrodes and active layer are arranged substantially parallel to the surfaces of the outer and inner plates. The planar electrodes are connected to an external power source. Electrical contact and connection to the energy source of the active layer are achieved via suitable connecting cables, such as flat conductors or thin-film conductors, which may optionally be connected to the planar electrodes via so-called bus bars, such as strips of conductive material or conductive embossed material. The thickness of the functional element is, for example, 0.4 mm to 1 mm.

[0031] The present invention further includes glass units for vehicles or buildings, said glass unit comprising at least a composite plate having electrically controllable optical properties. The composite plate includes an outer plate and an inner plate, which are interconnected via a thermoplastic interlayer, and functional elements having electrically controllable optical properties are embedded in said interlayer. The functional elements have an active layer, on which transparent planar electrodes are distributed at two surfaces. The glass unit further includes a control unit for electrically controlling the optical properties of the glass unit according to the method of the present invention, said control unit being connected to the planar electrodes of the functional elements and configured to apply a voltage between the planar electrodes.

[0032] In a preferred design, the functional element is a PDLC functional element, an SPD functional element, or an electrochromic functional element.

[0033] In a preferred design, the functional element is a PDLC (polymer-dispersed liquid crystal) functional element. The active layer of the PDLC functional element contains liquid crystal embedded in a polymer matrix. If no voltage is applied to the planar electrodes, the liquid crystal is oriented in a disordered manner, resulting in strong scattering of light passing through the active layer. If a voltage is applied to the planar electrodes, the liquid crystal is oriented in a common direction, and light transmission through the active layer is increased. However, other functional elements whose optical properties are variable based on liquid crystals can also be used, such as PNLC (polymer-networked liquid crystal) functional elements.

[0034] In another preferred design, the functional element is an SPD (suspended particle device). Here, the active layer contains suspended particles, wherein the absorption of light through the active layer can be altered by applying a voltage to the planar electrodes.

[0035] In another preferred design, the active layer of the functional element is an electrochemically active layer. Such functional elements are known as electrochromic functional elements. The transmission of visible light is related to the degree of ion embedding in the active layer, where ions are provided, for example, through an ion storage layer between the active layer and the planar electrode. Transmission may be affected by a voltage applied to the planar electrode, which induces ion migration. Suitable functional layers may, for example, contain at least tungsten oxide or vanadium oxide.

[0036] In a preferred design, the control unit includes a DC transformer and / or an inverter. Since the onboard voltage of a vehicle is, for example, 12 to 14V, this voltage is insufficient to operate the functional components. Therefore, the control unit is preferably equipped with a DC transformer. The DC transformer is configured to convert the DC voltage as a primary voltage to a higher secondary voltage (e.g., 65V). In an advantageous design, the secondary voltage can be from 5V to 70V. Furthermore, a temperature sensor and a voltage supply unit are coupled to the control unit.

[0037] An inverter is configured to convert secondary voltage to AC voltage, wherein the secondary voltage is applied to planar electrodes. This is particularly advantageous when the glass unit is installed in a vehicle and connected to the vehicle's onboard voltage. To convert the vehicle's DC voltage to AC voltage, the control unit includes an inverter. The AC voltage can range from 5 V to 50 V.

[0038] Composite panels can be equipped with opaque masking prints, particularly around the edge areas, as is common in the automotive industry, especially for windshields, rear window panels, and sunroof panels. The masking prints are typically made of enamel, which comprises glass frit and pigments, particularly black pigment. The printing ink is typically applied by screen printing and then fired. Such masking prints are applied to at least one of the panel surfaces, preferably to the interior space side surfaces of the outer and / or inner panels. The masking prints preferably frame the central transparent area and, particularly, protect the adhesive used to attach the composite panel to the vehicle body via the adhesive. If the control unit and temperature sensor are located on the inner panel, they are preferably located in the opaque edge areas of the masking print.

[0039] According to another aspect of the invention, a vehicle, particularly a passenger car, having a glass unit according to the invention is described.

[0040] Another aspect of the invention includes the use of the glass unit according to the invention in vehicles used for land, air or water transportation, especially in motor vehicles, for example as a windshield, rear window panel, side window panel and / or sunroof panel, as a functional unit, and as an installed part in furniture, equipment and buildings. Attached Figure Description

[0041] The invention will now be described in more detail with reference to the figures and embodiments. The figures are schematic and not to scale. The figures do not limit the invention in any way.

[0042] Figure 1 shows a schematic diagram of the glass unit.

[0043] Figure 2 is a graph showing the turbidity of an electrically controllable functional element based on the voltage applied to the planar electrode of the functional element.

[0044] Figure 3 shows a schematic diagram of one embodiment of the method according to the present invention.

[0045] Figure 4 is a graph showing the transparency of electrically controllable functional components based on voltage and temperature.

[0046] Figure 5 shows a schematic diagram of another embodiment of the method according to the present invention.

[0047] In the embodiments, the described components represent features of the invention that are to be observed independently of each other, and these features may also be considered as part of the invention individually or in combinations different from those shown.

[0048] Numerical descriptions should not be interpreted as precise values, but rather include tolerances of + / -1% up to + / -10%. Detailed Implementation

[0049] Figure 1 shows a schematic diagram of a glass unit 100, which can be installed, for example, in a motor vehicle or in a building. The glass unit 100 includes a composite panel 1. The composite panel 1 includes an outer panel 1a and an inner panel 1b, which are interconnected via an intermediate layer 3. The outer panel 1a has a thickness of 2.1 mm and is composed of soda-lime glass. The inner panel 1b has a thickness of 1.6 mm and is composed of clear soda-lime glass.

[0050] The composite panel 1 is equipped with a functional element 2 in the central region, which is nested within an intermediate layer 3. The intermediate layer 3 comprises a total of three thermoplastic layers, each constructed from a 0.38 mm thick thermoplastic film made of PVB. A first thermoplastic layer 3a is connected to the outer panel 1, and a second thermoplastic layer 3b is connected to the inner panel 1b. A third thermoplastic layer, located in between, surrounds the cut functional element 2 (PDLC multilayer film) substantially flush on all sides. The functional element 2 is thus embedded in the thermoplastic material on all sides and is therefore protected.

[0051] The composite panel 1 is equipped with a temperature sensor 4 for detecting temperature. The temperature sensor 4 is connected to a control unit 11, allowing the control unit 11 to determine the temperature of the composite panel 1 by means of the temperature sensor 4. The measurement signal from the temperature sensor 4 is thus transmitted to the control unit 11 and evaluated there, enabling the control unit 11 to acquire the temperature of the composite panel 1 and / or the functional element 2. The temperature sensor 4 is disposed within the composite panel 1. The temperature sensor is embedded in the intermediate layer 3. The temperature sensor 4 is here fastened to the surface of the inner panel 1b. Alternatively, the temperature sensor 4 may be externally fastened to the composite panel 1 or distributed to the composite panel. The temperature sensor 4 may also be disposed within the control unit 11 itself or in a fastening element, which the control unit 11 uses to fasten it to the composite panel 1. In principle, a temperature sensor 4 that measures temperature remotely without being directly fastened to or integrated into the composite panel 1, such as an IR sensor, may also be used, positioned in the environment of the composite panel and aligned with it.

[0052] The composite panel 1 may have a surrounding edge region equipped with an opaque masking print. This masking print is typically constructed of black enamel. The black enamel is screen-printed as a printing ink containing black pigment and glass frit and fired into the panel surface. The masking print is exemplarily applied to the inner space side surface of the outer panel 1a and also to the inner space side surface of the inner panel 1b. The side of the functional element 2 is covered by this masking print. The control unit 11 and the temperature sensor 4 may be arranged in the opaque edge region, i.e., bonded to the masking print of the inner panel 2. There, the control unit 11 does not interfere with the view through the composite panel and is visually inconspicuous. Furthermore, the control unit is located at a small distance from the side of the composite panel 1, so that only a short cable is needed advantageously to the electrical terminals of the functional element 2.

[0053] Figure 1 further illustrates the on-state of a glass unit 100 having a functional element 2 embedded in a composite panel 1. The glass unit 100 also includes a control unit 11 (also referred to as an ECU in motor vehicles), which is electrically connected to the functional element 2 via a closed switch 12, such that a voltage V can be applied to the functional element 2.

[0054] The voltage V applied between the two planar electrodes 10 of functional element 2 can be either a DC voltage or an AC voltage. In the case of a PDLC functional element, the voltage is an AC voltage. Control unit 11 is equipped with a DC transformer that converts the on-board voltage (primary voltage) into a higher DC voltage, such as 65V (secondary voltage). The secondary voltage must be high enough to achieve 100% switching of functional element 2. Control unit 11 is also equipped with an inverter that converts the secondary voltage into an AC voltage.

[0055] The optical properties of the glass unit 100 are controlled by means of the control unit 11. For this purpose, the control unit 11 is electrically connected to the two transparent planar electrodes 10 of the functional element 2.

[0056] Functional element 2 is a multilayer film composed of an active layer 9, two planar electrodes 10, and two carrier films. This multilayer film is commercially available as a PDLC multilayer film. The active layer 9 is disposed between the two planar electrodes 10. The active layer 9 comprises a polymer matrix with liquid crystal dispersed therein, which is oriented according to a voltage applied to the planar electrodes 10, thereby controlling optical properties. The carrier films are composed of PET and have a thickness of approximately 0.125 mm. The carrier films are equipped with a coating made of ITO with a thickness of approximately 100 nm, pointing towards the active layer 9, which forms the planar electrodes 10. The planar electrodes 10 are constructed without insulating wires. The planar electrodes are constructed as a single, continuous layer. The planar electrodes do not have segmented or partitioned sections.

[0057] Figure 2 shows the voltage V applied to the planar electrode at room temperature of approximately 25°C without using the method according to the invention. RMS A graph showing the turbidity of the PDLC functional element. The measurements collected in the graph constitute the calibration function of functional element 2, especially the temperature-related calibration function. The graph illustrates that turbidity does not change linearly with the applied voltage. To reduce turbidity by 50%, the voltage must be reduced by more than 50%.

[0058] Figure 3 shows a schematic diagram of one embodiment of the method according to the present invention. To obtain linear behavior of the optical properties of the functional element 2, an inverse function 300 is applied to a desired value 200 of turbidity. The inverse function 300 is determined from the calibration function of the functional element 2. As a result, a voltage value 400 is obtained, which can be applied to the planar electrode to achieve the desired transparency of the functional element 2.

[0059] Figure 4 is based on voltage V RMS The graph showing the temperature of functional element 2 illustrates the transparency of the electrically controllable functional element 2. This graph demonstrates the temperature dependence of transparency.

[0060] Figure 5 shows a schematic diagram of another embodiment of the method according to the present invention. Since the transparency of the functional element 2 is temperature-dependent, an inverse temperature-dependent function 300' is applied as a temperature-dependent linearization function to determine the voltage value 400. For this purpose, the temperature value 500 of the functional element 2 or the composite plate 1 is determined.

[0061] A major advantage of this invention is that, since the temperature detected by the temperature sensor can be taken into account when controlling the functional elements, the switching behavior of the glass unit can be improved by determining the temperature.

[0062] List of reference numerals in the attached diagram:

[0063] 1 Glass unit

[0064] 1a outer panel

[0065] 1b Inner Panel

[0066] 2 Functional Components

[0067] 3. Intermediate layer

[0068] 3a First thermoplastic layer

[0069] 3b Second thermoplastic layer

[0070] 4 sensors

[0071] 9. Active layer

[0072] 10 Planar Electrodes

[0073] 11 Control Unit

[0074] 12 switches

[0075] 100 glass units

[0076] 200 transparency value

[0077] 300, 300' inverse function

[0078] 400 voltage value

[0079] Temperature value of 500.

Claims

1. A method for electrically controlling at least one functional element (2) having electrically controllable optical properties embedded in a glass unit (100), wherein: • the glass unit (100) comprises a composite plate (1) having an outer plate (1a) and an inner plate (1b) interconnected via a thermoplastic interlayer (3, 3a, 3b); • the functional element (2) is disposed between the outer plate (1a) and the inner plate (1b) and has an active layer (9) having electrically controllable optical properties between a first planar electrode and a second planar electrode; • the optical properties are controlled by means of a control unit (11), wherein the control unit (11) is connected to at least two transparent planar electrodes of the functional element (2); • a voltage is applied between the planar electrodes by means of the control unit (11), characterized in that: • An inverse function (300, 300') is used to determine the value of the voltage, wherein the inverse function (300, 300') is used as a temperature-dependent linearization function, which is capable of linearizing a nonlinear calibration function, and • the temperature of the functional element (2) or the composite plate (1) is detected by means of a temperature sensor (4), • the temperature of the functional element (2) or the composite plate (1) is transmitted to the control unit (11), and • the control unit (11) determines the value of the voltage between the planar electrodes based on the temperature of the functional element (2) or the composite plate (1) and applies it.

2. The method according to claim 1, wherein the temperature sensor (4) is arranged on a flat conductor or flexible circuit board in the glass unit (100).

3. The method according to claim 1 or 2, wherein the temperature sensor (4) is a temperature-dependent resistance or IR sensor.

4. The method according to claim 1 or 2, wherein the temperature sensor (4) is spatially allocated to the functional element (2) and detects the actual temperature of the functional element (2).

5. The method according to claim 3, wherein the transparency value (200) of the functional element (2) is determined based on the temperature of the functional element (2).

6. The method according to claim 1 or 2, wherein the planar electrode is configured without insulating wires.

7. The method according to claim 1 or 2, wherein the linearization function is the inverse function of the calibration function of the functional element (2).

8. The method according to claim 1 or 2, wherein the temperature of the functional element (2) or the composite plate (1) is 30°C to 80°C.

9. The method according to claim 8, wherein the temperature of the functional element (2) or the composite plate (1) is in the range of 40°C to 60°C.

10. A glass unit having electrically controllable optical properties, the glass unit comprising: • a composite plate (1) having an outer plate (1a) and an inner plate (1b) connected to each other via a thermoplastic interlayer (3, 3a, 3b); • an electrically controllable functional element (2) disposed between the outer plate (1a) and the inner plate (1b) and having an active layer (9) having electrically controllable optical properties between a first planar electrode and a second planar electrode; and • a control unit (11) for controlling the optical properties of the functional element (2), wherein the control unit (11) is configured to perform the method according to any one of claims 1 to 9.

11. The glass unit according to claim 10, wherein the temperature sensor (4) is arranged in the edge region of the composite plate (1).

12. The glass unit according to claim 10 or 11, wherein the functional element (2) is a PDLC functional element, an SPD functional element, or an electrochromic functional element.

13. The glass unit according to claim 10 or 11, wherein the control unit (11) comprises a DC transformer and / or an inverter.

14. A means of transport having a glass unit (100) according to any one of claims 10 to 13.

15. The means of transport according to claim 14, wherein the means of transport is a passenger vehicle.

16. Use of a glass unit (100) according to any one of claims 10 to 13 in a means of transport for air or water traffic and as an embedded part in furniture, equipment and buildings.

17. The use according to claim 16, wherein the glass unit is used in a motor vehicle.

18. The use according to claim 16, wherein the glass unit serves as a wind deflector, rear window panel, side window panel and / or sunroof panel, and as a functional unit.

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