Heating system having a vehicle window pane

Abstract

The invention relates to a heating system comprising a vehicle window pane (1), in particular a rear window pane, and at least one heating device, characterised in that the vehicle window pane (1) is designed as a laminated glass window pane or as an individual glass window pane, the heating device comprises, as a heating element, at least one IR radiation source (3) having an IR wavelength range of between λ = 1.4 µm and 1.5 µm, and the IR radiation source (3) is arranged in or on a vehicle interior installation part (4) and the IR radiation source (3) is further directed with its beam path directly onto at least one planar heating region (H) of the vehicle window pane (1) or can be directed onto the heating region (H). The invention also relates to the use of such a heating system, preferably in motor vehicles.

Description

[0001] Heating system with a vehicle window

[0002] The invention relates to a heating system comprising a vehicle window, in particular comprising a rear window, and to the use thereof.

[0003] One challenge when driving a car is heating the windows, particularly the windshield, rear windows, and side windows, in order to prevent or eliminate icing or fogging of the window(s), which obstructs visibility. The heating of the windows, particularly the windshield, is usually done using heated air that is blown onto the windows via inlets. This type of heating is summarized under the Heating, Ventilation, and Air Conditioning (HVAC) method. For rear windows, such a method is described in DE000007012573 U. In addition to the enormous energy consumption, the inlets through which the hot air is transported and blown onto the windows require a lot of space. Furthermore, the outlet nozzles must be mounted in a specific geometric relationship to the windows, which in turn significantly limits the design and construction freedom.An additional problematic aspect in electric vehicles is that no waste heat from the engine can be used to heat the supply air for the HVAC method.

[0004] Heated vehicle windows are well known. They have been used primarily as heated windshields in motor vehicles and offer the possibility of conveniently removing ice or condensed moisture from the windshield by heating it. Such windows feature transparent, electrically conductive coatings, particularly silver layers. The coatings are electrically connected so that a current can be passed through them. This heats up the coating, which is responsible for the heating effect. Examples include WO2013 / 104438A1 and DE202014010748 U1.

[0005] One problem with electrically conductive coatings is their often high sheet resistance, which, for large dimensions of the windshield to be heated or for long current paths, requires a high operating voltage, which is certainly higher than the usual on-board voltages in vehicles. WO 2013 / 104439 A1 and EP 2803246 B1 disclose an electrically conductive coating for heating a windshield, which consists of different layers that can be used to slightly reduce the sheet resistance.

[0006] Furthermore, heat and thus energy loss through convection across the usually large window surfaces is very high. Another disadvantage of heatable coatings is that silver coatings, for example, are impermeable to high-frequency radiation. This impairs, for example, the reception of mobile phone signals, communication with cloud servers (the "Internet of Things"), and similar functions. This can lead to problems, particularly in the case of electric vehicles. Some vehicle manufacturers, especially electric vehicle manufacturers, therefore reject the use of silver-containing coatings.

[0007] A further challenge for electrically conductive coatings, which are often multi-layered, for heating vehicle windows is the visually appealing appearance, as well as compliance with required standards, for example with regard to light transmission and color neutrality, especially for windshields but also rear windows for vehicles.

[0008] For rear windows, the common method for defrosting and removing condensed moisture is the use of printed heating wires, for example, using Joule heating, also known as ohmic heating and resistance heating. The heating wires can be applied to a tempered window using silver printing. These clearly visible, printed stripes are undesirable, primarily from an aesthetic point of view. In addition, the heating prints (printed heating wires) must be applied directly to the tempered rear window and electrically connected via cables and connectors, and functionally connected, if necessary, to a control system or the on-board electronics.This requires additional process steps such as connecting wires and connectors, such as the printing and soldering of busbars (flat and busbar conductors), which must now be performed using lead-free alloys as required. This can lead to increased stresses in the glass and, as a result, glass breakage. The printed heating wires themselves, which are typically printed with silver, are also susceptible to damage. This can lead to the failure of entire heating lines and, as a result of damage, to the formation of hotspots.

[0009] The cables and connections must, in turn, be optically concealed, for example using cover prints, in order to achieve an appealing aesthetic appearance.

[0010] DE 101 10 142 B4 discloses a method for operating a heating device for a plastic window of a motor vehicle with an infrared radiator, wherein the infrared radiator is designed to emit infrared rays with an intensity maximum in the wavelength range from approximately 1700 nm to approximately 1900 nm and to emit infrared rays with an intensity maximum in the wavelength range from approximately 2500 nm to approximately 2800 nm, and during a predetermined heating period, infrared rays with an intensity maximum at least in the wavelength range from approximately 2500 nm to approximately 2800 nm are emitted and after the heating period, only infrared rays with an intensity maximum in the wavelength range from approximately 1700 nm to approximately 1900 nm are emitted.

[0011] DE 10 2008 017330 A1 discloses an arrangement for heating a window of a motor vehicle, wherein the window is assigned a heating device for heating the window, wherein the heating device comprises a device for emitting electromagnetic radiation which can be radiated onto the window.

[0012] US 2010 / 187211 A1 discloses a heating system for the vehicle cabin, comprising: a first infrared radiator operable to heat a target surface in front of the first infrared radiator within an interior of a vehicle cabin; a temperature sensor disposed in front of the first infrared radiator for detecting a measured temperature in front of the first infrared radiator; and a controller operatively coupled to the first infrared radiator for selectively operating the first infrared radiator to a target surface temperature within the interior of the vehicle cabin when an estimated surface temperature of a target surface, determined based on the temperature measured by the temperature sensor, falls below a prescribed temperature range below the target surface temperature.

[0013] GB 2 470 038 A discloses an infrared-based defrosting system for a vehicle windshield and DE 10 2009 010303 A1 discloses a heating device and a method for heating a window pane of a motor vehicle.

[0014] DE 41 22 462 C2 discloses a motor vehicle with a vehicle compartment having a plurality of panes and with at least one electrically operated infrared radiator in a housing, which is directed towards the inside of a windscreen on a console provided inside the vehicle, wherein the housing of the infrared radiator is manufactured in one piece with the console provided on the windscreen.

[0015] DE 10 2019 211 821 A1 discloses a heating device for a vehicle, comprising a sun visor with a front side and a rear side, which is arranged on a ceiling of an interior of the vehicle and is associated with a window pane of the vehicle, wherein a folded-in state and an unfolded state are provided for the sun visor, wherein the rear side faces the ceiling in the folded-in state, wherein the front side faces the window pane in the unfolded state, wherein a main heating source is arranged on the front side of the sun visor, which main heating source is designed to emit infrared radiation and to heat the window pane when the sun visor is in the unfolded state, and to heat the interior when the sun visor is in the folded-in state.

[0016] WO 2005 / 003047 A1 discloses a pane that can be heated using non-visible light. The pane is made of a material that is transparent to visible light and absorbs non-visible light.

[0017] There is therefore a need for improved, particularly effective and energy-efficient, heating systems for vehicle windows, especially rear windows, which avoid the disadvantages described.

[0018] The present invention is therefore based on the object of providing a heating system comprising a vehicle window, in particular a rear window, which can be operated particularly selectively, effectively and energy-efficiently and at the same time enables a visually appealing appearance of the vehicle windows, and is simple and cost-effective to manufacture.

[0019] These and other objects are achieved with the present invention by a heating system for vehicle windows according to claim 1. Preferred embodiments are evident from the subclaims.

[0020] The invention relates to a heating system comprising a vehicle window, in particular a rear window, which separates a vehicle interior from the external environment, and at least one heating device, wherein the heating device comprises at least one radiation source with an IR wavelength range between λ = 1.4 pm and 1.5 pm as a heating element, and the IR radiation source is arranged in or on a vehicle interior component and the IR radiation source is directed with its beam path directly onto at least one flat heating area of ​​the vehicle window or can be aligned onto the heating area. According to the invention, the vehicle window is designed as a laminated glass pane or as a single glass pane. As described above, the vehicle window is designed as a laminated glass pane or as a single glass pane. The vehicle window is therefore not a plastic pane.

[0021] The heating of the vehicle window according to the invention, i.e., defrosting or the removal of condensed moisture (defogging) using IR radiation, can be carried out significantly faster, more efficiently, and, in particular, more energy-efficiently than with the previously known electrically heated wires, electrically conductive heating layers, or heating using the heating, ventilation, and air conditioning (HVAC) method. The insertion or attachment of wires or printed circuit boards in or onto the vehicle windows, especially the rear window, as well as their necessary electrical contacts, can be completely eliminated.

[0022] The radiation source is an IR radiation source that directly impacts the vehicle window, preferably with a spatial obstacle between the radiation source and the window surface, and can act on it. In the infrared wavelength range of the radiation source provided in the invention, it advantageously has a high transmission value of > 80% for glass, while water molecules and ice exhibit high absorption coefficients in this electromagnetic radiation range, particularly at 1450 nm. This allows for selective, rapid, and efficient removal of condensed moisture (defogging) or frost and ice (defrosting) without the need to heat the vehicle window itself.

[0023] Due to its particular energy efficiency, the heating system according to the invention is particularly suitable for electric vehicles.

[0024] By eliminating heating wires or heating coatings in or on the vehicle windshield, several process steps can be eliminated during its production, resulting in simplified and significantly more cost-effective production of the vehicle windshield. Furthermore, the development and formation of functional layers and coatings, such as low-E layers, for the respective vehicle windshield integrated into the heating system is significantly less complex, and desired or prescribed quality and safety standards, such as light transmission and color neutrality, can be more easily achieved and maintained.The permeability of high-frequency radiation, for example, required for receiving mobile phone signals, communicating with cloud servers (“Internet of Things”), and the like, is not impaired by the heating system according to the invention, which requires no electrically conductive coating on or within the vehicle window, thus offering further advantages. Replacing, disposing of, or recycling damaged vehicle windows is significantly easier, which is of increasing interest and importance due to the increasing demand for sustainability and resource-efficient product manufacturing. In the simplest case, this involves only glass.

[0025] In a preferred embodiment of the heating system, the heating device is a radiation source in the IR wavelength range between A = 1.45 pm and A = 1.54 pm. In a particularly preferred embodiment of the heating system, the heating device is a radiation source in the IR wavelength range between A = 1.42 pm and A = 1.47 pm. It is not necessary for the emission band of the radiation source to completely cover the specified range. However, the emission band should at least lie within this range. The radiation source(s) is (are) expediently connected to a power supply device.

[0026] The radiation source of the heating device can, in particular, be a radiation source similar to an LED, which can also be referred to as an "IR-emitting diode." The LEDs are arranged and soldered on a printed circuit board (PCB) in the heating device in the usual way. The PCB, in turn, can be arranged and mounted on a suitable heat sink, for example, on a metal plate.

[0027] The radiation sources can, for example, be strip-shaped or spot-shaped and arranged and fastened in or on the vehicle interior component. Other geometric shapes or arrangements, for example in a matrix, are possible. Several individual radiation sources can also be arranged next to one another, spaced apart, or in a strip-shaped manner (close to one another). If several spot-shaped LEDs are arranged next to one another, in other words, a multi-part, strip-shaped radiation source can be designed as a heating device. This makes it possible to flexibly adapt the number and intensity of the radiation sources to the requirements for heating the respective vehicle window, for example with regard to the spatial and geometric conditions and the energy required for efficient heating.

[0028] In a preferred embodiment of the heating system, the heating area of ​​the vehicle window is heated by one or more IR radiation sources assigned to this area with an energy of at least 1 mW / cm 2 to effect defogging (removal of moisture) or defrosting (removal of frost and ice). According to the invention, heating is carried out with an energy application of between 1 mW / cm 2 and 90 mW / cm 2 , for example between 2 mW / cm 2 and 80 mW / cm 2 For example, using an LED with a wavelength in the range of approximately 1.45 pm results in an energy input of more than 80 mW / cm 2 .

[0029] A heating area is a surface area of ​​the vehicle window intended for heating by the radiation source. This can be the entire surface of the vehicle window or, for example, only the driver-relevant viewing area of ​​the rear window. The window surface can have multiple heating areas, or a heating area can be divided into several sub-heating areas, also called heating zones, which are then assigned to one or more heating devices with the radiation sources. Heating areas and / or heating zones can be arranged adjacent to one another, as required, or spaced apart from one another within the vehicle window surface.

[0030] If, in a preferred embodiment, the vehicle window has multiple heating areas or a heating area with multiple heating zones, each of which is preferably assigned at least one heating device with at least one radiation source, these assigned heating devices and, if applicable, the radiation sources of these heating devices or heating zones can be switched and operated independently of one another as needed. This advantageously further contributes to the heating system being operated particularly energy-efficiently.

[0031] In a further preferred embodiment, it is provided that the IR radiation source is functionally connected to at least one environmental sensor, in particular a temperature and / or humidity sensor and / or conductivity sensor.

[0032] In a preferred embodiment of the heating system according to the invention, the IR radiation source can be functionally connected to at least one control unit and / or on-board electronics.

[0033] In another preferred embodiment, the vehicle window, preferably the rear window, has a plurality of heating areas and / or one or more heating areas with a plurality of heating zones, each of which is assigned at least one radiation source, and these assigned radiation sources can be switched and operated independently of one another. The heating device can be functionally connected to a controller, in particular to on-board electronics, and / or to one or more environmental sensors, and these can communicate with one another. The environmental sensor(s) can in particular comprise one or more temperature sensors, humidity sensors, conductivity sensors, and / or a variety of other sensors, which can be designed to detect environmental conditions and states of the vehicle windows in connection with the removal of moisture fogging (defogging) and / or frost on the windows of a vehicle.During operation, the controller can monitor the status of the environmental sensors and automatically switch on the heating system, for example, to remove ice or condensation from the vehicle windows and / or to prevent frost and / or moisture from accumulating on the vehicle windows. During operation or starting of the vehicle, a controller in operative communication with the sensors can identify whether moisture is detected by the humidity sensor and / or whether the temperature sensor registers a temperature below a freezing threshold. Accordingly, based on the detected humidity level and / or the indicated temperature, the controller can determine whether a condition exists to automatically activate the heating system, i.e., switch it on to heat one or more of the vehicle windows and defog. Manual activation of the heating system can also be provided alternatively or additionally.

[0034] The vehicle window is preferably a rear window.

[0035] In a particularly preferred embodiment of the heating system according to the invention, the vehicle window is the rear window of a passenger car, and the vehicle interior component is, for example, a seat, in particular a headrest and / or the backrest of a seat, in particular a rear seat in the passenger compartment. However, the vehicle interior component can also be, for example, a trunk cover or part of the vehicle interior trim.

[0036] In another preferred embodiment of the heating system, the heating device is a heating module comprising a plurality of radiation sources, and the heating module, optionally as a prefabricated structural unit, is connected to the vehicle interior component. The connection can be formed, for example, by adhesive bonding or other fastening means. As described above, the vehicle window is designed according to the invention as a laminated glass pane or as a single glass pane. Preferably, the vehicle window is designed as a conventional, tempered laminated glass pane or as tempered and toughened single-pane safety glass (ESG). The vehicle window can in particular be designed as a conventional, tempered laminated glass pane or, as a rear window, usually as tempered and toughened single-pane safety glass (ESG).Advantageously, the heating system according to the invention requires no modifications or devices in, on, or on the vehicle window. Vehicle windows are already manufactured as standard from materials that exhibit high transmission for the electromagnetic infrared radiation of the radiation sources used for the heating device.

[0037] A vehicle window designed as a laminated glass pane comprises a first glass pane and a second glass pane, which are connected via a thermoplastic intermediate layer.

[0038] The thermoplastic intermediate layer comprises at least one layer of a thermoplastic bonding material, which preferably contains or consists of ethylene-vinyl acetate (EVA), polyvinyl butyral (PVB), or polyurethane (PU), or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The thermoplastic intermediate layer is typically formed from at least one thermoplastic film. The thickness of the film is preferably from 0.3 mm to 2 mm, with standard thicknesses of 0.36 mm and 0.76 mm being particularly common. The thermoplastic intermediate layer can also comprise multiple layers of thermoplastic material and, for example, be formed from multiple polymer films arranged flatly one above the other.

[0039] The vehicle window is preferably a window pane of a motor vehicle, rail vehicle, ship, or aircraft. It is particularly preferably the windshield, side window, rear window, or roof window of a passenger car or truck, most preferably the rear window. In a particularly advantageous embodiment, the vehicle is an electric vehicle. In other words, the advantages of the heating system according to the invention are particularly evident in electric vehicles.

[0040] The vehicle window, i.e. the first pane and the second pane of the laminated glass pane or the pane of the single glass pane, is preferably made of soda-lime glass, which is particularly common for rear windows. In principle, however, the vehicle window can also be made of other types of glass (e.g. borosilicate glass, quartz glass, aluminosilicate glass). The thickness of the pane can vary widely. Preference is given to panes with a thickness in the range of 0.5 mm to 10 mm, preferably from 1 mm to 5 mm. The various embodiments of the invention can be implemented individually or in any desired combination. In particular, the features mentioned above and those to be explained below can be used not only in the specified combinations, but also in other combinations or on their own without departing from the scope of the present invention, unless they are explicitly possible and described only as alternatives to one another.

[0041] A particular advantage of the heating system according to the invention is that an IR radiation source with an IR wavelength range between λ = 1.4 m and 1.5 pm is used. In this wavelength range, water molecules have a very high absorption coefficient and the vehicle window, whether designed as a laminated glass pane or as a single pane of glass, has a low absorption coefficient, whereby a very selective heating effect can be achieved. This helps to achieve the heating effect particularly quickly and in an energy-saving manner. Advantageously, according to the invention, the heating effect does not depend on the heating of the vehicle window itself, but is achieved selectively by the excitation of the water molecules by the IR radiation. The heating effect therefore occurs much more quickly than with previously used heating devices and, in addition, there is no heat loss due to convection and the large surface area of ​​the vehicle window.Thus, the effectiveness is significantly less dependent on the outside temperature than with previously known heating systems, which first have to heat the windows to ultimately remove condensation and ice. This is a further advantage of the heating system according to the invention.

[0042] The invention further relates to the use of a heating system according to the invention, as described above in various embodiments, in means of transport for traffic on land, in the air or on water, preferably in motor vehicles, particularly preferably in electric vehicles, preferably as a heating system for vehicle rear windows.

[0043] The invention is explained in more detail below using exemplary embodiments, with reference to the accompanying figures. They show, in simplified, schematic representations, not to scale:

[0044] Figure 1a schematic plan view of the heating device of a heating system implemented according to the invention in a car (partial view);

[0045] Figure 1b shows a schematic plan view of a rear window of a car heated according to the invention (partial view from the rear); Figure 1c shows a schematic view of the vehicle interior (partial view of the passenger compartment with rear seat) with a heating system for a rear window according to the invention;

[0046] Figure 2 shows an absorption spectrum of water (liquid state);

[0047] Figure 1a shows, in one embodiment, a schematic plan view of the heating device of a heating system implemented according to the invention in a passenger car (PV) 10, which is shown in a partial view with an open trunk lid encompassing the vehicle window 1, namely the rear window. In this embodiment, the heating device comprises several IR radiation sources 3 as heating elements, each of which is arranged in rows on the back of the headrests 4 of the rear seats in the vehicle interior 2. The heating device comprises the usual, necessary connections and lines. The LEDs are usually soldered to a circuit board, which is arranged, for example, on a cooling plate (heatsink).When the tailgate is closed, the IR rays are directed with their beam path (beam direction) P of the heating elements for heating onto the vehicle window 1 or can, if necessary, be directed onto the window surface as a heating area H manually or automatically using the heating device and / or heating module. The IR radiation sources 3 are preferably LEDs with a wavelength range between A = 1.4 pm and 1.5 pm; for example, an InGaAsP diode with a wavelength of 1450 nm can be used. This wavelength range corresponds to a frequency and wavelength range in which water molecules have a very high absorption coefficient for IR radiation. At the same time, the transmission of glass in this IR radiation range is particularly high at TL > 80% and only a small part is absorbed.In addition, LEDs in this range can offer a higher output power and are cheaper and more easily accessible than LEDs in the wavelength range between 1.8 pm and 2.0 pm or between λ = 2.8 pm and 3.0 pm. The IR radiation sources 3 are designed and / or arranged in a strip shape. The arrows indicate the direction of radiation of the IR radiation by way of example and schematically. The IR radiation is absorbed by the water molecules, which are heated by the excitation from the radiation and thereby evaporated. A particular advantage of the invention is that IR radiation in particular can be used with the most precise wavelength possible and in the frequency range in which water molecules have a very high absorption coefficient, and in this way a very selective heating effect can be achieved. This helps to achieve the heating effect particularly quickly and in an energy-saving manner.Energy efficiency is an extremely important criterion for future product developments. Advantageously, the heating effect according to the invention does not depend on the heating of the vehicle window 1 itself, but is achieved selectively through the excitation of the water molecules by the IR radiation. Therefore, the heating effect occurs much more quickly than with previously used heating devices, and additionally, there is no heat loss due to convection and the large surface area of ​​the vehicle window 1. Thus, the dependence of the effect on the outside temperature is significantly lower than with previously known heating devices, which must first heat the windows to ultimately remove condensation and ice.

[0048] The heating device can be functionally connected to a controller (not shown), in particular to on-board electronics, and / or to one or more environmental sensors (not shown), and these can communicate with each other. The environmental sensor(s) can in particular comprise one or more temperature sensors, humidity sensors, conductivity sensors, and / or a variety of other sensors, which can be designed to detect environmental conditions and states, in particular of the rear window, in connection with the removal of moisture mist (defogging) and / or frost on the windows of a vehicle 10. During operation, the controller can monitor the status of the environmental sensors and automatically switch on the heating system, for example, to remove ice or condensate from the vehicle windows and / or to prevent frost and / or moisture from accumulating on the vehicle windows.During operation or starting of the vehicle 10, a controller in operative communication with the sensors can identify whether moisture is detected by the humidity sensor and / or whether the temperature sensor registers a temperature below a freezing threshold. Accordingly, based on the detected moisture level and / or the indicated temperature, the controller can determine whether a condition exists to automatically activate the heating system to heat and defog one or more of the vehicle windows. Manual activation of the heating system may also be provided alternatively or additionally.

[0049] Figure 1b shows a schematic plan view of a vehicle window 1 of a passenger car 10 heated according to the invention, in a view from the rear. In the embodiment shown in Figure 1b, the vehicle window 1 is a rear window and, in this configuration, has a heating area H which, for example, is divided into three heating zones H1, H2 and H3 arranged directly adjacent to one another. The heating area H can be the entire window surface or only a partial area of ​​the vehicle window 1, for example a field of vision for a driver which is to be freed from fogging caused by condensed moisture or ice that obstructs the view.In the embodiment shown, the vehicle window 1 has a heating area H with a plurality of heating zones H1, H2 and H3 arranged next to one another, to which at least one heating device, for example the heating modules M1, M2 and M3 (shown in Figure 1a), is preferably each assigned, each of which has a plurality of IR radiation sources 3. Alternatively, it is possible for such heating zones H1, H2, H3 to be designed as circumferential heating zones H1, H2, H3 that decrease in size from the edge of the vehicle window 1 towards the center, or as heating zones H1, H2, H3 arranged one above the other in the vertical direction in the surface of the vehicle window 1. If different heating devices, i.e. individual IR radiation sources 3 or, as shown here, heating modules M1, M2, M3 and M4 with a plurality of IR radiation sources 3, are assigned to the heating areas H or the heating zones H1, H2, H3 of a heating area H, these heating devices can preferably be switched and operated independently of one another.The IR radiation sources 3 of a heating module M 1 , M 2 and M 3 can also be switched and operated independently or independently of one another. The switching can be automated by means of the functional connection to the environmental sensors and / or a controller, as described in Figure 1a. This advantageously further contributes to the heating system being operated in a particularly energy-efficient manner and, for example, when the battery level is low, only the absolutely necessary heating area of ​​the vehicle window 1 is freed from condensed moisture or ice, such as the required field of vision for a driver. In the installed position, the upward-facing edge is referred to as the upper edge (roof edge). The downward-facing edge of the vehicle window 1 in the installed position (motor edge) is referred to as the lower edge. The edges running in between are referred to as side edges.

[0050] Figure 1c shows a schematic view of the vehicle interior 2 in a partial view of the passenger compartment with a rear seat with a heating system according to the invention with a vehicle window 1, which is a rear window, wherein the heating modules M1, M2, M3 and M4 with the IR radiation sources 3 (shown in Figure 1a) are arranged on the back of the headrests 4a or the backrest 4b of the seats or on the trunk cover 4c (vehicle interior installation part) or in the wall paneling of the passenger compartment. The IR radiation sources 3 are aligned with their beam direction towards the vehicle window 1 as the heating area H. The heating modules can also preferably be arranged with several radiation sources, for example on a carrier plate (panel), which can then be connected as a structural unit to a vehicle interior installation part, optionally movable and alignable with the vehicle window 1, for example electrically controlled. Such arrangements can optionallybe provided as pre-assembled units, which can simplify production. Figure 2 shows the absorption spectrum of water in the liquid state. The diagram shows that water molecules have a particularly high absorption coefficient, for example at wavelengths of approximately 1.45 pm, 1.9 pm and 2.95 pm (marked with vertical arrows). In a preferred embodiment, a radiation source 3 in the IR wavelength range, preferably between A = 1.42 pm and A = 1.47 pm, is used as the heating device for the heating system, since the absorption and excitation of the water molecules, and thus the resulting heating and evaporation, is particularly high in this preferred wavelength range.Advantageously, it has been shown that, with glass, the transmission in the relevant wavelength range is particularly high at > 80%, so that the radiation energy can be used efficiently for defrosting and evaporating water in the corresponding heating areas of the vehicle window 1, for example, a rear window. The radiation source 3 can, for example, be an InGaAsP diode with a wavelength of 1450 nm. This wavelength corresponds to a wavelength range in which water molecules have a particularly high absorption coefficient, whereby the excitation of the water molecules is also particularly high and a particularly rapid, selective, and efficient evaporation is achieved.

[0051] List of reference symbols

[0052] 1 vehicle window (preferably rear window)

[0053] 2 Vehicle interior

[0054] 3 IR radiation source (heating element) 4 Vehicle interior component (headrest, trunk cover, seat back, etc.)

[0055] 4a Headrest

[0056] 4b Back of seat

[0057] 4c trunk cover

[0058] 10 passenger cars / vehicle M heating module

[0059] M1, M2, M3, M4 heating module

[0060] H Heating area

[0061] H1 , H2, H3 Heating zones Arrows P Beam direction of the IR radiation source

Claims

Patent claims 1. Heating system, comprising a vehicle window (1), in particular a rear window, and at least one heating device, characterized in that the vehicle window (1) is designed as a laminated glass pane or as a single glass pane, the heating device comprises at least one IR radiation source (3) with an IR wavelength range between A = 1.4 pm and 1.5 pm as a heating element, and the IR radiation source (3) is arranged in or on a vehicle interior installation part (4) and furthermore the IR radiation source (3) is directed with its beam path onto at least one flat heating area (H) of the vehicle window (1) or can be aligned onto the heating area (H).

2. Heating system according to claim 1, characterized in that the heating device is an IR radiation source (3) with an IR wavelength range between A = 1.42 pm and A = 1.47 pm.

3. Heating system according to claim 1 or 2, characterized in that the IR radiation source (3) comprises at least one LED.

4. Heating system according to one of claims 1 to 3, characterized in that the heating area (H) of the vehicle window (1) is heated by one or more IR radiation sources (3) with an energy of at least 1 mW / cm 2 is applied.

5. Heating system according to one of claims 1 to 4, characterized in that the IR radiation source (3) is functionally connected to at least one environmental sensor, in particular a temperature and / or humidity sensor and / or conductivity sensor.

6. Heating system according to one of claims 1 to 5, characterized in that the IR radiation source (3) is functionally connected to at least one control unit and / or on-board electronics.

7. Heating system according to one of claims 1 to 6, characterized in that the vehicle window (1) has in the heating area (H) several heating zones (H1, H2, H3), to which in each case at least one heating device is associated with at least one IR radiation source (3) and these associated IR radiation sources (3) are preferably switchable and operable independently of one another.

8. Heating system according to one of claims 1 to 7, characterized in that the vehicle window (1) is a rear window.

9. Heating system according to claim 8, characterized in that the vehicle window (1) is the rear window of a passenger car (10) and the vehicle interior installation part (4) is a seat, in particular a headrest (4a) and / or the backrest of a rear seat (4b).

10. Heating system according to one of claims 1 to 9, characterized in that the heating device is a heating module (M) which comprises a plurality of IR radiation sources (3) and the heating module (M) is connected as a prefabricated unit to the vehicle interior installation part (4). 1 1 . Use of the heating system according to one of claims 1 to 10 in means of transport for traffic on land, in the air or on water, preferably in motor vehicles, preferably as a heating system for vehicle rear windows.

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