DE202020005499U1 - Composite pane with electrically controllable optical properties and composite pane arrangement - Google Patents

Abstract

Laminated pane arrangement, in particular a vehicle glazing unit, with
- A composite pane (1) with electrically controllable optical properties, comprising an outer pane (1a) and an inner pane (1b) which are connected to one another via a thermoplastic intermediate layer (3),
wherein a functional element (4) with electrically controllable optical properties is embedded in the intermediate layer (3), comprising an active layer (5), to which transparent flat control electrodes (8, 9) are assigned on both surfaces, between a first carrier film (6) and a second carrier film (7), and
wherein a transparent heating resistance layer (11) is applied on the inside of the inner pane (1b) or the outer pane (1a) or within the intermediate layer (3), on which a busbar (11a, 11b) for connection to a Heating current source is arranged,
- a control unit (13) for controlling the optical properties of the functional element (4),
- a temperature sensor (16),
- A heating current source (15) for applying a heating current to the busbars (11a, 11b) of the heating resistor layer (11) and
- A heating control unit (14) for controlling the supply of heating current to the heating resistance layer for setting a predetermined temperature or a predetermined temperature range of the active layer (5) of the functional element (4), the heating control unit (14) being suitable for heating current to be supplied as soon as a temperature measured by the temperature sensor (16) falls below a predetermined limit value in order to increase the temperature above the limit value.

Description

The invention relates to a composite pane with electrically controllable optical properties and to a composite pane arrangement which comprises such a composite pane. It also relates to a vehicle, in particular a road vehicle, with such a composite pane and composite pane arrangement.

Optoelectronic functional elements with electrically controllable optical properties have long been known in great variety and are used in industrial mass production, for example in TV sets, laptops, mobile phones / smartphones and tablets.

Composite panes with electrically controllable functional elements are also known as such. The optical properties of the functional elements can be changed by an applied electrical voltage. An example of such functional elements are PDLC (polymer dispersed liquid crystal) functional elements, which for example consist of DE 102008026339 A1 are known. The active layer contains liquid crystals which are embedded in a polymer matrix. If no voltage is applied, the liquid crystals are disordered, which leads to a strong scattering of the light passing through the active layer. If a voltage is applied to the surface electrodes, the liquid crystals align themselves in a common direction and the transmission of light through the active layer is increased.

Windshields and also glass roofs have been proposed in which an electrically controllable sun visor is implemented by means of such a functional element in order to replace the conventional mechanically foldable sun visor in motor vehicles. Windshields with electrically controllable sun visors are known from, for example DE 102013001334 A1 , DE 102005049081 B3 , DE 102005007427 A1 and DE 102007027296 A1 .

SPD and PDLC functional elements are commercially available as multilayer films, the active layer and the flat electrodes required for applying a voltage being arranged between two carrier films, typically made of PET. During the manufacture of the composite pane, the functional element is cut out of the supplied multilayer film in the desired size and shape and placed between the films of an intermediate layer, by means of which two glass panes are laminated together to form a composite pane.

US5111329A discloses a composite pane with an electrically controllable functional element and a heating coating which is used to de-ice the composite pane.

As is known, LCD arrangements have a clearly temperature-dependent switching characteristic and, in particular at low temperatures, relatively long switching times. The aforementioned PDLC and SPD functional elements also have this property, which impairs their acceptance by users and consequently also by manufacturers of road vehicles.

The present invention is based on the object of providing an improved composite pane with electrically controllable optical properties, in which advantageous switching characteristics, in particular with acceptable switching times, can be implemented over a wide outside temperature range. There is also the task of specifying a corresponding arrangement.

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

The composite pane according to the invention comprises at least one outer pane and one inner pane, which are connected to one another via a thermoplastic intermediate layer. The composite pane 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 the pane facing the interior. The outer pane is the term used to describe the pane facing the external environment. The intermediate layer is used to connect the two panes, as is customary with composite panes.

The outer pane and the inner pane are preferably made of glass. In principle, however, they can also consist of plastic. The thickness of the outer pane and the inner pane can vary widely and thus be adapted to the requirements in the individual case. The outer pane and the inner pane preferably have thicknesses from 0.4 mm to 3.5 mm, particularly preferably from 1 mm to 2.5 mm. The panes can be clear, tinted or colored. When using the composite pane as a windshield in a car, care must be taken that the windshield has 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, 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 composite pane according to the invention contains a functional element with electrically controllable optical properties, which is embedded in the intermediate layer. In the context of the invention, the functional element is also referred to as an optoelectronic functional element. The functional element is 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.

The 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 the variable optical properties, which 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 said 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 a preferred embodiment, the functional element is a PDLC functional element. The active layer of a PDLC functional element contains liquid crystals which are embedded in a polymer matrix. In a further 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. In principle, however, it is also possible to use other types of controllable functional elements, for example electrochromic functional elements. Such controllable functional elements and their mode of operation are known per se to the person skilled in the art, so that a detailed description can be dispensed with at this point.

The surface electrodes and the active layer are typically arranged essentially parallel to the surfaces of the outer pane and the inner pane. The surface electrodes are electrically connected to an external voltage source in a manner known per se. The electrical contacting, as well as the connection to the energy source for temperature control of the active layer, is realized by means of suitable connecting cables, for example foil conductors, which are optionally connected to the surface 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 0.1 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 flat electrodes can contain, for example, 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 flat electrodes preferably have a thickness of 10 nm to 2 μm, particularly preferably from 20 nm to 1 μm, very particularly preferably from 30 nm to 500 nm.

The functional element is in particular in the form of a multilayer film with two outer carrier films. In such a multilayer film, the surface electrodes and the active layer are typically arranged between the two carrier films. The outer carrier film here means that the carrier films form the two surfaces of the multilayer film. The functional element can thereby be provided as a laminated film which can advantageously be processed. The functional element is advantageously protected from damage, in particular corrosion, by the carrier films.

The heating resistance layer provided according to the invention can be applied to the inner surface of the inner pane, applied to the inner surface of the outer pane or embedded in the intermediate layer, for example on a carrier film between two lamination films. The inner side denotes that surface of the respective pane which faces the intermediate layer. The heating resistance layer is used to raise the working temperature of the active layer of the optoelectronic functional element when the composite pane is in use at low outside temperatures in such a way that a switching time that is acceptable for the specific function of the functional element is achieved. The desired switching time or switching characteristic depends on the specific function of the functional element and will be shorter for optoelectronic displays, such as a head-up display, than for a sun visor element.

It is possible to use the invention known per se and, for example, by the applicant to realize commercially available heatable vehicle windows with a transparent heating resistor layer. In principle, the same materials and layer thicknesses can be used for the heating resistor layer as were mentioned above for the transparent surface electrodes of the functional element - however, with the proviso that the surface resistance is not as small as possible, but rather sufficient to achieve rapid heating of the composite pane. Silver or silver alloy layers, which are typically present in addition to dielectric layers in the heating resistor layer, are preferred from the current point of view.

According to the current level of knowledge of the inventors, it is advantageous if the heating resistor layer can be configured to set the temperature of the active layer to a temperature in the range above 0 ° C, preferably above 3 ° C, particularly preferably above 5 ° C. This temperature range has been recognized as advantageous for commercially available optoelectronic functional elements for composite panes; For other functional elements, other target temperatures of the active layer can be preferred, and the flat control electrodes are then to be configured to achieve these other temperatures.

Provision is made for elongated connections, in particular busbars, to be provided on opposite edges of the optoelectronic functional element for connecting the heating current source. Busbars are known per se and especially for film-like optoelectronic functional elements PDLC or SPD type and elongated, typically linear, thick layers of a printed conductive paste (e.g. silver paste) used in heated vehicle windows. However, it is also possible to develop and use particularly suitable, e.g. particularly thin and largely transparent, connection elements for the implementation of the invention.

In addition to the above-mentioned use of heatable composite panes known per se (essentially over the entire surface) in the context of the invention, this can also be implemented with heating resistance layers which cover only part of the pane surface. Then it is provided in particular that the part of the pane surface covered with the heating resistor layer includes at least that area in which the optoelectronic functional element is placed, for example the area of a head-up display or an electronically controllable sun visor.

In principle, the temperature sensor can be arranged anywhere in the vehicle, so that temperature sensors that are already present in the vehicle can be used. It is particularly advantageous if the temperature sensor is integrated in the laminated pane, because the temperature of the laminated pane can be determined particularly precisely in this way. In a very particularly preferred embodiment, the temperature sensor is arranged in or near the optoelectronic functional element within the intermediate layer. Regardless of the fact that when the laminated pane according to the invention is used in road vehicles, external and internal temperature sensors are usually present on / in the vehicle anyway, such a design enables more precise detection of the temperature of the active layer and thus also a more reliable setting of the desired temperature or the desired temperature range of this layer. If the requirements placed on the setting accuracy are lower, the signals from existing temperature sensors (outside the laminated pane) can also be used to implement the invention.

The composite pane is preferably provided as a window pane, particularly preferably as a window pane of a vehicle, in particular a motor vehicle, a building or a room. In a particularly advantageous embodiment, the composite pane is the windshield of a motor vehicle, in particular a passenger car, with an electrically controllable sun visor, which is implemented by the functional element. While the lateral edges and the upper edge of such a functional element are typically covered by the usual covering pressure in the edge area of the pane, the lower edge is arranged in the transparent area of the pane and is therefore not masked and visible. This lower edge of the functional element is preferably sealed according to the invention. The optically inconspicuous sealing is particularly advantageous here.

An electrically controllable sun visor can make the conventional, mechanically pivoting sun visor superfluous. This frees up space in the passenger compartment of the vehicle, reduces the weight of the vehicle and avoids the risk of a collision with the sun visor when braking hard or in an accident. In addition, the electrical control of the sun visor can be perceived as more convenient than the mechanical folding down.

The sun visor is electrically controlled, for example, by means of buttons, rotary controls or slide controls that are integrated in the vehicle's fittings. However, a button for regulating the sun visor can also be integrated into the windshield, for example a capacitive button. Alternatively, the sun visor can also be made using non-contact methods, for example by recognizing gestures, or, depending on this, by a camera and suitable Evaluation electronics determined the state of the pupil or eyelid can be controlled. An optoelectronic functional element, which does not function as a sun visor but, for example, as part of a head-up display, can basically be controlled in its optoelectronic properties in a similar manner and temperature-controlled in a manner according to the invention.

The composite pane arrangement according to the invention also has a control unit for controlling the optical properties of the optoelectronic functional element, a heating current source for applying a heating current to the busbars of the heating resistor layer and a heating control unit for controlling the supply of heating current to the heating resistor layer for setting a predetermined temperature or a predetermined temperature range the active layer of the optoelectronic functional element.

The signal from the temperature sensor serves as an input variable for controlling the energy supply to the busbars of the heating resistor layer. For this purpose, the temperature sensor is connected to the heating control unit. The heating control unit is suitable for automatically supplying heating current as soon as a temperature measured by the temperature sensor falls below a predetermined limit value in order to increase the temperature above the limit value. This limit value is preferably 0 ° C because it has been shown that an increase in temperature above 0 ° C leads to a reduction in the switching times in the case of commercially available functional elements. The effect is particularly pronounced with an increase above 3 ° C., in particular above 5 ° C., so that a limit value of 3 ° C. is particularly preferred and a limit value of 5 ° C. is very particularly preferred.

The heating current source and the associated heating control unit can be components which are usually used to operate heatable vehicle windows known per se. From the current point of view, however, an embodiment of that component adapted to the invention is preferred, in which additional means are provided for controlling the heating operation in accordance with the special requirements of the optoelectronic functional element. Such a design therefore allows heating current to be applied to the heating resistance layer not only to clear the corresponding pane, but also when the pane has no fogging or preventive heating would be required to avoid fogging.

In particular, it is provided that the heating control unit is connected to the temperature sensor on the input side.

In an advantageous embodiment, the heating control unit is equipped with a control circuit in order to automatically keep the temperature above the said limit value, for example a proportional control circuit, in particular an integral or differential control circuit.

The invention also comprises a road vehicle, in particular a passenger car, which is equipped with a composite pane arrangement according to the invention.

The composite pane arrangement according to the invention can be operated according to a method in which the heating control unit automatically supplies a heating current as soon as a temperature measured by the temperature sensor falls below a predetermined limit value, whereby the temperature measured by the temperature sensor is increased or raised above the limit value.

• 1 eine Draufsicht auf eine erste Ausgestaltung der erfindungsgemäßen Verbundscheibe als Windschutzscheibe mit elektrisch steuerbarer Sonnenblende,
• 2 einen Querschnitt durch die Windschutzscheibe aus 1,
• 3 eine vergrößerte Darstellung des Bereichs Z aus 2 und
• 4 eine schematische Darstellung zur Ausführung der Erfindung in Art eines Funktions-Blockschaltbildes.

The invention is explained in more detail with reference to figures and exemplary embodiments. The drawing is a schematic representation and is not true to scale. The figures do not restrict the invention in any way. Show it:

• 1 a plan view of a first embodiment of the composite pane according to the invention as a windshield with an electrically controllable sun visor,
• 2 a cross section through the windshield 1 ,
• 3 an enlarged view of the area Z. 2 and
• 4th a schematic representation of the implementation of the invention in the form of a functional block diagram.

1 shows schematically a windshield 1 with electrically controllable sun visor S. as a preferred embodiment of the composite pane according to the invention with electrically controllable optical properties as part of a composite pane arrangement according to the invention, and 2 and 3 each show details of this. The windshield 1 includes an outer pane 1a and an inner pane 1b that have an intermediate layer 3 are connected to each other. The outer pane 1a has a thickness of, for example, 1.6 or 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 windshield has an upper edge facing the roof in the installed position D. and a lower edge facing the engine compartment in the installed position M. on.

The windshield 1 is in an area above the central viewing area B. (as defined in ECE-R43) with an electrically controllable sun visor S. fitted. The sun visor S. is through a commercially available PDLC multilayer film as a functional element 4th formed in a recess in the intermediate layer 3 is stored. The height of the sun visor is, for example, 21 cm.

On the side edges of the functional element 4th (the sun visor S. ) each is a functional element busbar 4a , 4b formed for electrical connection to a (not shown) control circuit.

As 1 and 2 show is almost the entire area of the windshield 1 (with the exception of the immediate lateral edge areas) with a heating resistor layer 11 provided on the inner surface of the inner pane 2. There is a heating current busbar on each of the side edges 11a , 11b upset. With the heating resistor layer 11 it is a transparent, closed coating (for example made of silver), as is known per se to the person skilled in the art from commercially available heatable windshields for cars. With the heating current busbars 11a , 11b these are conductive thick-film strips (also known as such), for example made from a thermally treated silver paste.

As from the cross-sectional view of 2 can be seen, comprises the intermediate layer 3 here a total of three thermoplastic layers 3a , 3b , 3c each formed by a thermoplastic film with a thickness of 0.38 mm made of PVB. The first thermoplastic layer 3a is with the outer pane 1a connected, the second thermoplastic layer 3b with the inner pane 1b . The intermediate third thermoplastic layer 3c has a cutout in which the cut PDLC multilayer film is inserted essentially precisely, that is to say approximately flush on all sides. The third thermoplastic layer 3c thus forms a kind of passe-partout for the approximately 0.4 mm thick functional element 4th , which is encapsulated all around in thermoplastic material and thus protected.

The first thermoplastic layer 3a has a tinted area 3a ' on that between the functional element 4th and the outer pane 1 is arranged. The light transmission of the windshield is thereby in the area of the sun visor 4th additionally reduced and the milky appearance of the PDLC functional element 4th attenuated in the diffusive state. The aesthetics of the windshield is made much more appealing. The first thermoplastic layer 3a points in the area 3a ' for example, an average light transmission of 30%, with which good results are achieved. The area 3a ' can be tinted homogeneously. Often, however, it is more visually appealing if the tint is towards the lower edge of the functional element 4th becomes smaller, so that the tinted and the non-tinted area flow into one another. In the case shown, the bottom edges of the toned area are 3a ' and the PDLC functional element 4th arranged flush. But this is not necessarily the case. It is also possible that the tinted area 3a ' via the functional element 4th survives or that, conversely, the functional element 4th over the tinted area 3a ' survives.

The controllable functional element 4th is like 3 shows a multilayer film consisting of an active layer 5 between two flat electrodes 8th , 9 and two carrier foils 6th , 7th . The active layer 5 contains a polymer matrix with liquid crystals dispersed in it, which align depending on the electrical voltage applied to the surface electrodes, whereby the optical properties can be regulated. The carrier foils 6th , 7th consist of PET and have a thickness of, for example, approx. 0.2 mm. The carrier foils 6th , 7th are with an active layer 5 facing coating made of ITO with a thickness of about 100 nm, which the surface electrodes 8th , 9 form. The surface electrodes 8th , 9 can be connected to the on-board electrical system via busbars (not shown) (for example formed by screen printing containing silver) and connecting cables (not shown).

As usual, the windshield has a circumferential, peripheral cover print 10 by an opaque enamel on the interior surfaces (in the installed position facing the interior of the vehicle) of the outer pane 1a and the inner pane 1b is trained. The distance of the functional element 4th to the top D. and the side edge of the windshield is smaller than the width of the covering print 10 so that the side edges of the functional element 4th - with the exception of the central field of vision B. pointing side edge - through the masking print 10 are covered. The electrical connections (not shown) are also expediently in the area of the cover print 10 attached and thus hidden.

4th Figure 3 is a schematic representation of a composite pane assembly 12th who have favourited a composite pane (windshield) 1 of the type explained above, in the form of a functional block diagram. The composite pane 1 is shown here in the form of an exploded view, and the designation of its components corresponds to the designation in 1 until 3 .

The functional element busbars 4a , 4b of the functional element 4th are connected to a control circuit via connecting lines inside and outside the laminated pane (not specifically designated) 13th of the optoelectronic functional element 4th connected, which can be constructed in a known manner and whose construction and mode of operation are therefore not explained here. On the other hand, there are the heating current busbars 11a , 11b on the heating resistor layer 11 via a heating control unit with a heating current source 15th connected. Also this heating device of the composite pane 1 is basically known from commercially available heatable windshields with a transparent heating resistance layer and is therefore also not described in more detail here.

Inside the windshield 1 and adjacent to the optoelectronic functional element 4th is a temperature sensor 16 of a known type provided with an input of the heating control unit 14th connected is. The signal from the temperature sensor 16 , which is the actual temperature of the active layer of the functional element 4th is used as an input variable for controlling the energy supply to the connections (busbars) 11a , 11b the heating resistor layer 11 .

The implementation of the invention is not limited overall to the aspects highlighted above and the examples described above, but is also possible in a large number of modifications which are within the scope of the appended claims.

List of reference symbols

1

Windshield

1a

Outer pane

1b

Inner pane

3

thermoplastic intermediate layer

3a

first layer of intermediate layer 3

3a '

tinted area of the first layer 3a

3b

second layer of intermediate layer 3

3c

third layer of intermediate layer 3

4th

Functional element with electrically adjustable optical properties

4a, 4b

Function element busbar

5

active layer of the functional element 4

6th

first carrier film of the functional element 4

7th

second carrier film of the functional element 4

8, 9

Flat electrode of the functional element 4

10

Cover print

11

Heating resistance layer

11a, 11b

Heating current busbar

12th

Composite pane assembly

13th

Control circuit of the optoelectronic functional element

14th

Heating control unit

15th

Heating power source

16

Temperature sensor

B.

Viewing area

D.

Top edge of the pane

M.

Lower edge of the pane

S.

Sun visor

X-X '

Cutting line

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102008026339 A1 [0003]
• DE 102013001334 A1 [0004]
• DE 102005049081 B3 [0004]
• DE 102005007427 A1 [0004]
• DE 102007027296 A1 [0004]
• US 5111329 A [0006]

Claims (10)

Laminated pane arrangement, in particular a vehicle glazing unit, with - A composite pane (1) with electrically controllable optical properties, comprising an outer pane (1a) and an inner pane (1b) which are connected to one another via a thermoplastic intermediate layer (3), wherein a functional element (4) with electrically controllable optical properties is embedded in the intermediate layer (3), comprising an active layer (5), to which transparent flat control electrodes (8, 9) are assigned on both surfaces, between a first carrier film (6) and a second carrier film (7), and wherein a transparent heating resistance layer (11) is applied on the inside of the inner pane (1b) or the outer pane (1a) or within the intermediate layer (3), on which a busbar (11a, 11b) for connection to a Heating current source is arranged, - a control unit (13) for controlling the optical properties of the functional element (4), - a temperature sensor (16), - A heating current source (15) for applying a heating current to the busbars (11a, 11b) of the heating resistance layer (11) and - A heating control unit (14) for controlling the supply of heating current to the heating resistance layer for setting a predetermined temperature or a predetermined temperature range of the active layer (5) of the functional element (4), the heating control unit (14) being suitable for heating current to be supplied as soon as a temperature measured by the temperature sensor (16) falls below a predetermined limit value in order to increase the temperature above the limit value. Composite pane arrangement according to Claim 1 , wherein the functional element (4) is a PDLC functional element, PNLC functional element, SPD functional element or electrochromic functional element. Composite pane arrangement according to Claim 1 or 2 , wherein said limit value is 0 ° C, preferably 3 ° C, particularly preferably 5 ° C. Composite pane arrangement according to one of the Claims 1 until 3 , wherein the functional element (4) is provided in a first sub-area (S) of the laminated pane and the heating resistance layer (11) extends over a second sub-area of the laminated pane which includes the first sub-area. Composite pane arrangement according to one of the Claims 1 until 4th , wherein the heating resistance layer (11) covers the major part of the surface, in particular the entire surface, of the composite pane. Composite pane arrangement according to one of the Claims 1 until 5 , wherein the temperature sensor (16) is integrated in the laminated pane. Composite pane arrangement according to one of the Claims 1 until 6th wherein the composite pane (1) is designed as a windshield or roof glazing of a road vehicle, in particular a car. Composite pane arrangement according to one of the Claims 1 until 7th , the heating control unit (14) being connected on the input side to the temperature sensor (16). Composite pane arrangement according to one of the Claims 1 until 8th wherein the heating control unit (14) is equipped with a control circuit to keep the temperature above said limit value. Road vehicle, in particular a car, with a composite pane arrangement according to one of the Claims 1 until 9 .

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