DE20308376U1 - Connection device for a multi-layer surface element and surface element equipped with electrical functional elements - Google Patents

Abstract

Connection device for a multilayer surface element (1), which comprises a first rigid disc (2) provided with electrical functional elements and a second rigid disc (4) which is connected to the side of the first rigid disc provided with the functional elements, one of the rigid discs at least has a recess (11; 11 ') for establishing an electrical connection to the functional elements, characterized in that in said recess (11; 11') an insert part (12; 12D, 12S) with an edge thereof in between the two rigid discs (2, 4) lying plane and / or an undercut of the recess engaging behind the projection (13; 13 ') is fixed, and that the insert part (12; 12D, 12S) acts as an abutment for fastening at least one connecting part electrically connected to the functional elements (15) serves.

Description

The invention relates to a Connection device for a multi-layer surface element equipped with electrical functional elements with the features of the preamble of claim 1, and on a surface element equipped with such a connection device.

It is common knowledge that electrical conductive thin-film systems operated as heating resistors by applying an electrical voltage can be. There are manifold applications of these in both the vehicle and construction sectors Technology.

Generally these include flat Substrates, e.g. B. glass panes, deposited layer systems at least a metallic layer, e.g. B. made of silver, and (in the case of transparent layer systems) dielectric layers on both sides of the silver layer, possibly also blocker layers made of different materials, sometimes also top layers to increase the mechanical resistance of the layer structure. In many cases also properties reflecting the infrared radiation Layer systems used as thermal insulation.

Adjustment is usually problematic a homogeneous current density in those used as a heating layer Layer systems. Above all, locally overheated areas with high Avoiding current density, so-called "hot spots" the heating layer for this purpose in many applications stripe Surface electrodes. These exist e.g. B. from thin applied metal strips or printed electrically highly conductive, possibly baked colors and enable a current introduction and dissipation on the broadest possible Base. However, it is enough such connections mostly not optically aesthetic claims and must therefore be concealed. Since they are mostly on the edge of the substrate, however, in many applications, e.g. B. in vehicle window panes with little effort possible.

It is also known the current flows and distributions in such heating layers by fine lines to influence which the heating layer in individual, electrically parallel to each other Subdivide sections or current paths, the ohmic resistances among each other preferably are the same.

In the German patent application 102 08 552.8 becomes a plate element with an electrically conductive coating ( "Heating layer") described, which is for direct connection to standard household voltages suitable. It essentially consists of a multi-layer composite structure that a first rigid disc along with the heating layer deposited thereon includes an adhesive layer and a second rigid disc. In the area of an electrical connection of the heating layer drill the second rigid disc. In the area of this Bore are two areas of the heating layer with different polarity close together. On each of these areas is one on the heating layer applied electrode provided, each with a power supply Soldering connected is. The current flow between the two connection poles belonging to the same heating layer is mentioned in the Way by dividing the heating layer using fine lines directed.

DE-U1-201 07 908 describes a connection device described in which an electrically conductive coated glass pane is provided with holding elements in the form of clamp fittings, which at the same time as a carrier for electrical Serve contacts. Spring tongues are integrated into the clamp fittings lie electrically conductive on the coating of the glass pane or pressed on this become.

Describes in another context DE-A1-199 58 879 an insulating glass pane with a pane made of laminated glass, electrical functional elements (solar cells) are embedded in their adhesive layer are. Their electrical connection lines are through a recess one of the composite washers and the opposite rigid washer of the insulating glass, being the area of this implementation in the space between the panes of the insulating glass by an annular spacer is surrounded. The lines can can also be guided through a hollow pin of a point holder, the one for attaching the insulating glass pane to a substructure is used.

In the field of fittings and fastenings for laminated glass panes it is known (DE-A1-39 08 983, DE-C2-43 25 024, DE-U1-87 01 693), to provide recesses in one of the rigid disks, in the fastening elements be used firmly. The latter can have radially projecting projections, which extend into the composite adhesive layer and in the finished Grip behind the glass pane. If necessary, their recesses can have an undercut. For the latter case has also been used for undercut dowels for laminated glass fastenings described (DE-A1-38 11 249). The other surface side of these laminated glass panes remains completely in each case unharmed. The latter sources do not deal with electrical connection devices.

The invention is based on the object Basically, a connection device of the type mentioned above to improve and create a surface element equipped with it.

This object is achieved with the Features of claim 1 solved. The independent claim 16 relates to a connection device according to the invention equipped surface element. The characteristics of the independent claims subordinate claims give advantageous developments of these objects on.

According to the invention, the exception is taken tion of a rigid disk, an insert part that serves as an abutment for fastening at least one connecting element that is electrically connected to the functional elements. This insert has or forms a (radial) projection, which anchors it in a form-fitting manner in the recess.

As electrical functional elements heating elements, in particular heating layers, come into consideration, but also solar elements, sensors etc., each in a multilayer Structure are embedded and electrically contacted to the outside Need to become. For the here to be described structure of the connection device or Part of the function is the function of the elements of of minor importance.

The functional elements can both on the rigid disc with the recess and on the opposite this lying rigid disc can be arranged. Also conceivable are statements in which both rigid disks with electrical functional elements, z. B. electrodes for Electroluminescent lighting elements or solar cells are provided, and with one or more connection elements according to the invention be equipped.

The said projection of the insert can stare the edge of the recess in between the two Reach behind the flat layer (adhesive layer level). you this insert part is then already before the disc assembly fix in the recess so that the protrusion in the adhesive layer can be embedded. The thickness of the projection is then less than the thickness of the adhesive layer.

The projection can also be an undercut or reach behind a chamfer of the recess inside the composite. This can be done in a manner known per se through a multi-part insert be realized, the individual parts together in the recess itself be set. You can also use a suitable insert Undercut anchors use, which forms the said projection only when it in the Recess is inserted and clamped in it. Both types can advantageously be attached after the composite pane has been produced.

The insert part becomes special preferably as the basis of a collection point for all electrical interface functions of the surface element used.

It initially forms the basis for the actual ones electrical connection contacts, preferably as spring contacts accomplished become. For the intended use in a surface heating element with relatively high operating voltages, they only have to transmit small (alternating) currents; also in buildings heating elements used are generally not exposed to vibrations. Thus, corrosion problems are not expected to be found in others Areas of application (vehicle construction) as increased contact resistance can impact. About that lets out the contact area hermetically seal if necessary so that moisture and dirt cannot penetrate.

If necessary, the electrical contacts can be closed but also by the functional elements or their electrodes Soldering made or just in addition be secured. Soldering techniques are known that allow such solder joints without direct contact with the heat source melt safely (induction or laser soldering), and possibly even through the coated disc can be applied without however destroying the coating.

The insert can be used as the basis of a Serve connector with which a connecting cable for the functional elements can be electrically connected. Of course, a fixed connection line can also be used be provided from a connection box specified on the insert led out is and possibly has a plug at its free end.

In a preferred further variant there is also at least one switching element in the area of the insert part provided for on-off control of the functional elements. This switching element can be used in the "surface heating element" according to a further advantageous variant of at least one Controllable temperature sensor be the actual temperature of the heating layer in the connection area detected. Because in this area the local feed of electrical power the highest Current densities are likely to occur you will arrange the at least one temperature sensor there.

Such temperature sensors can also even as a current limiter (e.g. PTC thermistor, its electrical / ohmic Resistance increases with increasing temperature) and thus the switching element mentioned if necessary, if a suitable characteristic is provided. Possibly. can additionally an electrical fuse can be provided to that Functional element electrically protected.

In yet another advantageous variant, the insert part can also form the basis for an evaluator or receiver for control signals with which a functional element / surface heating element can be addressed and switched on and off individually by remote control. In the case of heating, these control signals are e.g. B. generated using room thermostats and temperature sensors. They can be transmitted via separate lines or as a bus line via the supply lines already available. In the latter case, the supply or mains voltage coded control pulses are superimposed, which can be electronically filtered out in the connection device of the surface heating element mentioned. However, the control signals are preferably transmitted wirelessly by radio, infrared, etc. gene, and in the area of the connection device, a suitable receiver and decoder is provided along with downstream switching or control elements.

In addition, the insert can as the basis for one manually adjustable temperature limit can be used with priority over the possibly provided internal temperature sensor the setting of a maximum electrical power consumption and thus the maximum actual temperature of the panel heater below the absolute maximum temperature specified in the factory of the surface heating element in question allows.

One is in a particularly preferred embodiment all required Components as much as possible miniaturize (e.g. as a microchip or processor) and put them in a housing or summarize a junction box that with little Can attach effort to said insert. Screws can be provided for connection become. You could but also a (detachable) Provide snap-in connection, if this is also the required Tightness of the contact area can be achieved. Possibly. could also have an adhesive connection between the insert and the junction box.

You can fasten it at the same time the said junction box also the electrical (spring) contacts connect with the functional elements. This has the advantages that on the one hand, a predefined contact pressure is not exceeded, and that, on the other hand, if the junction box is later loosened and removed The functional elements are also de-energized for maintenance or repair purposes or become electrically passive.

All active elements of the connection device can possibly from an anyway applied operating voltage of the functional elements, if necessary after appropriate Adjustment of the voltage level to be supplied electrically. You could but also self-sufficient using batteries that feed into the junction box be used.

In the connection area, too with little effort operational indicators can be provided that recognize leave whether the functional elements are switched on or active or ready for operation ("was standing by "). If it is a transparent surface element, so can these displays are light signals whose light is the surface element penetrates. It goes without saying that they are not covered by opaque lamination or the like. are covered or, if appropriate, corresponding viewing windows in such a lamination are provided.

With all the differences it is the Connection device described here for the commonly used point fasteners for (glass) plates but also conceivable a connection point with the ones described here Features to use as a fastening point for the surface element, if the fastener to the required on the electrical side Lets you adjust conditions and mounting on a substructure is possible. The latter can e.g. B. Hanging devices of the surface element or elements wear that with corresponding abutments on the -corresponding stably designed junction box correspond. Otherwise, becomes the surface element with suitable other means, e.g. B. attack at its edge (such as frames, brackets etc.), fixed in its installation situation or integrated flush in a wall / window front.

The connection device according to the invention can be advantageous practically everywhere on the surface of the surface element attach, be it near the edge, be it in the central area. Of course, at Requirement for the same surface element several such connection devices are provided if, for. B. several independently operable heating fields or solar cell modules can be connected have to.

When placing the connection device for a panel heating An essential parameter remains the demand for the most homogeneous possible Current density in the heating layer to be fed, so that this results certain restrictions for can reveal the location of the connection device.

More details and advantages of the object of the invention go from the drawing of exemplary embodiments a connection device for a surface heating element and their detailed description below out.

It doesn't show in simplified to scale presentation

1 an overall perspective view of a surface heating element with a connection device according to the invention;

2 a view of the connection area with an inserted part for attaching the connection device;

3 a sectional view of a first embodiment of the connection device according to the invention along the line III-III in 1 ;

4 one of the 3 corresponding sectional view of a second embodiment of the connection device according to the invention;

5 another of the 3 corresponding sectional view of a third embodiment of the connection device according to the invention.

According to 1 is a surface heating element 1 in the form of a composite disc with a first rigid disc 2 , an intermediate layer 3 and a second rigid disc 4 executed. The first rigid disc 2 is preferably a thermally toughened glass pane on its the intermediate layer 3 facing surface with a heating layer 5 is provided in the form of an electrically conductive coating. The heating layer 5 consists from a composition and / or layer sequence that is suitable for operation as a surface heating layer and, if necessary, is sufficiently thermally resilient for tempering the glass pane. Suitable layer systems have been described many times in the prior art, so that there is no need to go into them here. They can be produced with high transmission for visible light, that is to say transparent.

Appropriate means ensure that the said coating 5 all the way along the edge of the surface heating element 1 is passivated, that is to say that there is neither an electrically conductive contact with its outer or end face, nor the risk of a corrosive attack on the layer material from the outside. For example, you can at a small distance from the outer edge of the surface heating element 1 a continuous dividing line in the coating 5 provide that serves both purposes. Alternatively, a narrow circumferential strip along the edge of the surface heating element can also be used in a manner known per se 1 Leave completely free of the layer material or remove it later. In any case, using the intermediate layer 3 thermoplastic adhesive plastic material (e.g. polyvinyl butyral (PVB), ethylene vinyl acetate (EVA)) creates a hermetic seal of the marginal gap. It is understood that the material of the intermediate layer works well with the material of the coating 5 is selected compatible.

One recognizes in 1 the essential components of the electrical supply to the heating layer 5 , namely initially two strip-shaped surface electrodes 6 that are on either side of the two poles of the heating layer 5 dividing line isolating from each other 7 are arranged. The course of the current path between the two electrodes is through in the heating layer 5 introduced structural lines and results from the drawing. A junction box 8th with a connection cable (only indicated in sections) 9 is at the place of electrical contacting of the heating layer 5 or the pair of electrodes 6 attached to the second rigid disc. All electrical devices or interfaces at one point on the surface heating element are particularly advantageous 1 summarized locally.

Deviating from the representation in 1 the electrodes can of course also have shapes other than strips (e.g. semicircles). Furthermore, structural lines can already be started in the area of the heating layer covered by the electrodes, so that each electrode is electrically contacted with a plurality of current paths connected in parallel. Such a configuration or structuring of the heating layer along with its connection area can be necessary above all if, contrary to the illustration, the current feed should not be possible near the edge.

In 2 you can see the area of the electrical connections of the surface heating element in a plan view, in which the junction box is omitted. The disc 4 , which can also be made of tempered glass or plastic, has a hole 11 , in which a sleeve-shaped insert 12 is firmly used. Its outer contour is the diameter or the outline of the hole 11 adapted as exactly as possible. With a cantilevered lead 13 , designed here as a ring shoulder, engages behind this insert 12 the edge of the hole 11 in the level of the intermediate layer 3 , Through the free interior of the insert 12 are the heating layer 5 , the two electrodes 6 and the dividing line 7 visibly exposed. The areas on which the electrical connection contacts can come into contact are indicated as gray rectangular fields.

The insert part 12 may include form elements for fixing and securing the connection device against twisting. In this embodiment, the lugs are formed on the wall of its bore with bores into which screws can be screwed. Deviating from the illustration, these shaped elements can be arranged asymmetrically in order to only allow further components to be inserted in the correct position.

The 3 shows more details of an exemplary construction of the electrical connection device according to the invention in section, the same parts with the same reference numerals as in 1 and 2 are provided. One recognizes the multilayer structure of the surface heating element. From the rigid disk 2 only part of its thickness is shown, and a double dash-dotted line across the rigid disc 4 indicates that their thickness is also shortened. It is understood that these two rigid disks are significantly thicker than the intermediate layer 3 are. Their material is in the area of the electrodes 6 and the junction box (only partially indicated here) 8th recessed to allow unimpeded access to the electrodes 6 to enable. This recess must be made by melting the intermediate layer before connecting the two rigid panes 3 be dimensioned so that the adhesive material cannot penetrate to the electrodes.

In the present illustration, the diameter of the hole is 11 in relation to the thickness of the disc 4 rather drawn too small; it is understood that the bore is dimensioned sufficiently wide for the type of connection device provided.

Optical lamination of the connection area is not necessary for the function, but only serves aesthetic purposes. When installed, the disc 2 , ie the side of the surface heating element facing away from the connecting device, the visible side of which form. The connection area of the electrodes is only for example purposes 6 an opaque layer 10 between the heating layer 5 and provided the glass surface that covers this area outwards. The same effect can of course also be achieved by other means, e.g. B. by tinting the rigid disc 2 overall in the mass, applying a decor on the outer surface and / or designing the heating layer itself as a mirror, for. B. by dispensing with anti-reflective coating on their substrate-near side.

Furthermore, the electrodes themselves can also be used as decorative elements by giving them an optically appealing appearance. Then you could look at the opaque layer 10 dispense.

As already in 2 recognizable, is in the hole 11 the second rigid disc 4 the sleeve-shaped insert 12 attached. Its axial length corresponds approximately to the thickness of the rigid disc 4 (a few millimeters) and it still protrudes into the level of the intermediate layer 3 into it. Its radially protruding projection 13 engages behind the edge of the hole 11 so the insert part 12 it is positively secured against being pulled out.

As noted above, this insert must be connected before the two rigid washers are connected 2 and 4 in the hole 11 be used. Only by melting the thermoplastic intermediate layer 3 it will be finalized. You can see in the drawing that the lead 13 is still underpinned by the material of the intermediate layer.

The insert part 12 forms the basis for the junction box 8th , Two dash-dotted vertical lines indicate a screw connection between the two parts. With the junction box 8th is a support block 14 in the bore of the insert 12 attached, from which two spring contacts 15 against the electrodes 6 extend and bear against them in an electrically conductive manner. Also a symbolically indicated temperature sensor 16 is made using the support block 14 and the insert part 12 in contact with the coated surface of the rigid disc 2 held. It is used to record the actual temperature in the contact area of the electrodes 6 , The support block 14 becomes correct -ggf. forced into the insert by appropriate form elements 12 inserted so that the spring contacts 15 come into contact with the respective intended electrode, and then fixed. The support block can be a fixed unit with the junction box 8th form and together with this on the insert 12 be determined.

The spring contacts are sufficient 15 for the intended use of the surface heating element 1 the requirements for a safe, long-lasting electrical connection. Nevertheless, if necessary, they could additionally be soldered, in particular with the aid of a suitable pre-tinning. B. through the coated disc 2 could be fed through.

Switch symbols for a switch 17 and a transistor 18 represent the electrical or electronic equipment of the support block 14 or the junction box 8th and can each represent a plurality of corresponding elements. Except for passing the electrical supply voltage from the connection cable 9 to the electrodes 6 additional control and switching tasks are assigned to this area of the connection device.

A switching element has the measured values of the temperature sensor 16 evaluate and if necessary switch off the power supply to the heating layer at least temporarily if the actual temperature should exceed a permissible threshold. However, it is also possible to provide a switching element for securing against temperature overruns, which in a manner known per se only limits the electrical power consumed to permissible values.

At least one switch that is electronic or can be electromechanical, controls the power supply to the heating layer. In principle, this switch can be switched manually locally, of sensors -z. B. from the temperature sensor 16 or from a remote control device to be controlled. As already mentioned, the latter can be part of an automatic Room temperature control (air conditioning, etc.), but can also in principle arbitrarily from Be controllable by hand.

If the control signals are transmitted wirelessly, there is in the junction box 8th or in the carrier block 14 to provide a suitable receiver along with a decoder and other switching means (e.g. amplifiers). If the control signals are transmitted via lines, suitable evaluation elements must be provided for this, in particular in the event that control signals are present via the power supply lines (cables 9 ) are transmitted and have to be filtered out on site.

Display elements for the operating state of the surface heating element are not shown here 1 , In a preferred variant, these can be implemented as light signals (light-emitting diodes) and, for. B. in the area of the dividing line 7 between the spring contacts 15 and next to the temperature sensor 16 be arranged so that they are from the outside of the rigid disc 2 are visible from here. They are also electrical via the support block 14 fed and from the switching elements mentioned 17 . 18 controlled.

After completion and functional test of the connection device, a joint seal can be used if necessary 19 the transition from the pane surface to the junction box 8th be sealed. Such a seal can of course also deviate from the illustration directly between the underside of the junction box 8th and arrange the disc surface.

The 4 shows in one of the 3 Corresponding sectional view of a variant of an insert, which is here in an undercut hole 11 ' the second rigid disc 4 is used. So far che components as in 2 are shown, they have the same reference numerals and will not be discussed further. The insert is in two parts with an undercut plug 12D and a sleeve screw 12S executed. Such undercut anchors are already known from many glass applications. Also the production of undercut or countersunk holes 11 ' in glass panes is technically mature.

The undercut dowel 12D can be made in the hole from the outside after the assembly 11 ' be used. You then screw the sleeve screw 12S one that can be made of metal or a high-strength plastic. Vertical lines along their outer edges indicate their self-tapping external thread. When screwing in, the deformation of the undercut anchor is shown 12D to a radially projecting projection 13 ' on. This clearly fills the undercut chamfer of the hole 11 ' so far that it cannot be pulled out axially. At the same time is the sleeve screw 12S fixed radially and axially in the bore by engagement of its external thread in the dowel.

A possible penetration of the undercut anchor 12D In the level of the intermediate layer, excessive local tensions must not result, which could cause local delamination or even breakage of a pane. If in doubt, the material of the intermediate layer, if it is not sufficiently flexible, will be in the area of the bore 11 ' as far as drawn - so to the edge - so that the dowel can expand freely into the interlayer level.

The sleeve screw itself may only be screwed in to a specified depth so that it does not enter the bottom of the hole 11 ' hits the electrodes and this or the heating layer 5 damaged. Nor should it be with the contact springs 15 meet.

In contrast to a load-bearing glass fastening, no high acting forces are to be expected in the present application, so that the clamping forces of the dowel do not have to be particularly high. Still, it may be necessary to use the washer 4 also made of toughened glass, the bore 11 ' is to be introduced before pretensioning.

In a particularly advantageous variant, the junction box 8th and the sleeve screw 12S be combined into a fixed unit. You could then use the Ge housing of the junction box as a lever to screw in the sleeve screw by hand, the bottom of the junction box being on the top of the disc 4 at the edge of the hole 11 ' comes to rest, forms a depth stop. In this unit, the support block can be fixed in the correct position with the spring contacts and, if necessary, the temperature sensor.

While the insert part in both 3 and 4 practically flush with the main surface of the rigid disc 4 completes, the junction box rises slightly above this surface. Because this side of the panel heater 1 is usually facing away from the viewer / user in the installed state, possibly opposite a wall or is built into one, on the one hand the visual perception of the connection device remains limited to the lamination (or possibly on the opaque electrodes designed as decorative elements), on the other hand Dangers due to unauthorized or accidental manipulation of the connection device practically excluded. If a handle for operating a control element of the connection device is to be provided, this will of course preferably be in an easily accessible place, e.g. B. close to the edge of the panel heating element.

If based on the 4 for the "undercut hole" application in the second rigid disc 4 only the undercut dowel was discussed, but can be used if necessary, especially if the washer is rather thin 4 less than 5 mm, other components suitable for this purpose as an insert part of the type mentioned earlier analogous to the insert part 12 according to 2 be used.

The execution according to 5 combines a connection device according to the invention with a plate element in which the electrical functional elements to be connected are located on the second rigid disk 4 located with the hole 11 is provided. In contrast to the variants described above, there is no direct contact between the spring contacts 15 and the surface electrodes 6 the heating layer 5 intended. The lead 13 of the insert 12 Rather, it serves here as connecting bridges 20 with the surface electrodes 6 keep in contact after the insert 12 in the hole 11 the rigid disk 4 inserted and fastened in it. Since the insert part with the junction box 8th can be braced and thus the lead 13 under tension against the surface electrodes 6 this point of contact is not particularly critical. The surfaces of the connection bridges coming into contact with the surface electrodes can be roughened or provided with tips in order to allow the connection bridges to penetrate the surface electrodes slightly. However, as already mentioned above, soldering can also be carried out here by pre-tinning the connecting bridges and / or the surface electrodes by supplying heat.

The from the surface electrodes 6 opposite ends of the connecting bridges 20 protrude into the interior of the insert 12 into it. There they form - as equivalents to the surface electrodes of the previous design cases - contact surfaces for the spring contacts 15 , so that these are electrically connected via a connecting bridge after each installation 20 with the respective "actual" surface elec trodes 6 are securely connected.

The connection bridges 20 are preferably firmly in the insert 12 integrated to make the assembly of the connection device as simple as possible. This can e.g. B. by overmolding the connecting bridges 20 (narrow metal strips) with the plastic material of the insert 12 can be achieved in its design.

The dividing line can be seen again 7 between the two poles of the heating layer 5 and the opaque layer 10 , on which the heating layer is deposited in the contact area. In addition, here is another opaque layer 10 ' on the inner side of the rigid pane in the composite 2 provided, which optically conceals the contact area and can also be designed as a decorative element. Depending on requirements, one or both opaque layers can optionally be omitted, since they are irrelevant for the function of the connection device or the plate element.

During the adhesive intermediate layer 3 passes through in this representation in the contact area, however, if necessary, it can also have a recess analogous to this variant 3 and 4 be provided.

In the 5 Although no temperature sensor is shown, it goes without saying that a suitable sensor element for detecting the actual temperature in the connection area can also be provided in this embodiment variant. It would be conceivable, for. B., an additional thermal sensor similar to the jumper shown here 20 train and bring into contact with the heating layer or a surface electrode.

When using the described here Connection device for electrical functional elements of other types, e.g. B. in thin-film solar cells or sensors for Fogging or precipitation, as mentioned at the beginning, becomes more fundamental Construction opposite the embodiments shown here not changed. One can of course deviate only a single contact or a plurality of the drawings of contacts in the respective recess.

Claims (23)

Connection device for a multi-layer surface element ( 1 ), which has a first rigid disk provided with electrical functional elements ( 2 ) and a second rigid disk which is connected flatly to the side of the first rigid disk provided with the functional elements ( 4 ), one of the rigid disks having at least one recess ( 11 ; 11 ' ) For producing an electrical connection to the functional elements, characterized in that in said recess ( 11 ; 11 ' ) an insert ( 12 ; 12D . 12S ) with an edge in the between the two rigid panes ( 2 . 4 ) lying plane and / or an undercut of the recess engaging behind the recess ( 13 ; 13 ' ) and that the insert ( 12 ; 12D . 12S ) as an abutment for attaching at least one connecting part that is electrically connected to the functional elements ( 15 ) serves. Connection device according to claim 1, characterized in that the recess ( 11 ) is provided in the rigid disk provided with the functional elements or in the other rigid disk. Connection device according to claim 1 or 2, characterized in that in the region of the recess ( 11 ; 11 ' ) at least two areas of the functional elements with different polarity are brought together and that each of them with a connecting part attached to the insert part ( 15 ) is electrically contacted. Connection device according to Claim 1 or 2 or 3, characterized in that each connection part has at least one spring contact (which is electrically contacted with the functional element) ( 15 ) includes. Connection device according to one of the preceding claims, characterized in that in the region of each connection part a flat electrode which can be electrically connected to the latter ( 6 ; 20 ) of the functional element is provided. Connection device according to one of the preceding claims, characterized in that the insert part ( 12 ) sleeve-shaped and into the recess ( 11 ) is used, with its projection ( 13 ) the edge of the recess in the plane of the intermediate layer ( 3 ) engages. Connection device according to claim 1 or 6, characterized in that the projection ( 13 ) of the insert ( 12 ) with at least one contact agent ( 20 ) is provided, which is used to establish an electrical connection between at least one connection part ( 15 ) and a functional element ( 5 ) is provided, this functional element of that rigid disc ( 4 ) is assigned, in the recess ( 11 ) the insert ( 12 ) is arranged. Connection device according to claim 7, characterized in that a contact means as a connecting bridge ( 20 ) which is in the interior of the sleeve-shaped insert ( 12 ) a contact surface for a connector ( 15 ) and on a surface of the projection ( 13 ) a contact surface for connecting to the functional element ( 5 ) having. Connection device according to one of the preceding claims, characterized in that the insert a dowel, especially an undercut dowel ( 12D ) using a screw ( 12S ) in the recess ( 11 ' ) is set. Connection device according to claim 9, characterized in that the screw as a sleeve screw ( 12S ) is designed with an external thread, the interior of which forms a receptacle for further components of the connection device. Connection device according to one of the preceding claims, characterized characterized that they have means for attaching or hanging the sheet element on a substructure, especially on a building wall, is provided. Connection device according to one of the preceding claims for a with an electrically conductive coating, hereinafter as a heating layer ( 5 ) referred to as a functional element provided surface element. Connection device according to claim 12, characterized by at least one temperature sensor ( 16 ) for recording an actual temperature of the heating layer ( 5 ). Connection device according to claim 13, characterized by a temperature sensor ( 16 ) controllable switching element ( 17 . 18 ) to interrupt or reduce the heating current when a specified temperature threshold is exceeded. Connection device according to one of claims 12 to 14, characterized by a manually operated Adjuster for specifying a temperature threshold of the heating element. Connection device according to one of claims 12 to 15, characterized by a receiver for contactlessly transferable control signals and a switching device controllable by the receiver ( 17 . 18 ) for remote controllable switching on and off of the heating layer. Connection device according to one of the preceding claims, characterized by at least one display element, in particular a light signal, for the Operating state of the functional elements of the surface element. Connection device according to one of the preceding claims, characterized by a connection box ( 8th ) in the form of a housing as a cover to the outside. surface element with electrical functional elements embedded between two rigid plates and at least one connection device according to one of the preceding Expectations. Surface element according to Claim 19, of which a rigid plate is provided with an electrically conductive coating ( 5 ) coated glass pane ( 2 ), in particular a toughened glass pane. surface element according to claim 19 or 20, characterized in that at least in the area of the recess or the connection device on the of an optical lamination is provided on the side facing away from the recess is. surface element according to one of claims 19 to 21, characterized in that on one of its rigid disks in the area of the connection device at least one electrode for Establishing the electrical contact between the electrical functional elements and the connection device is arranged. surface element according to one of claims 19 to 22, characterized in that there is at least one display element for the Operating state of its functional elements includes.