METHOD AND ARRANGEMENT FOR DE-ICING A TRANSPARENT WINDOW USING AN ELECTRIC HEATING DEVICE

Abstract

A method to retrofit a transparent window which does not comprise an electric heating device, such as a vehicle windshield, with a transparent window having an electric heating device. The method includes (i) removing from the vehicle the transparent window which does not comprise an electric heating device, (ii) installing a transparent window, provided with an electric heating device, such as a heating layer, and at least one temperature sensor, to obtain a retrofitted heating transparent window, (iii) connecting the electric heating device to a voltage supply device such that by applying a heating voltage to the transparent window, and (iv) connecting a remote control device with the at least one temperature sensor and the voltage supply device.

Claims

1. A method to retrofit a transparent window which does not comprise an electric heating device with a transparent window having an electric heating device the method comprising: a. removing from the vehicle the transparent window which does not comprise an electric heating device b. installing a transparent window, provided with an electric heating device in particular a heating layer, and at least one temperature sensor, to obtain a retrofitted heating transparent window, c. connecting the electric heating device to a voltage supply device and applying a heating voltage to the transparent window and, d. connecting a remote control device with the at least one temperature sensor and the voltage supply device.

2. The method according to claim 1, wherein the electric heating device is used for de-icing and/or defogging the retrofitted transparent window.

3. A method for de-icing and/or defogging a transparent window retrofitted in accordance with the method of claim 1 comprising: a. measuring a window temperature before an initial application of a heating voltage, wherein the method is terminated if the window temperature exceeds a lower temperature threshold value and wherein the heating voltage and a heating period are selected such that a heating power corresponding to a resistance less than 10 ohms () per square meter (m2) of window area is generated, and b. applying a heating voltage between 30 and 60 volts to the heating device to apply a heating power corresponding to a resistance less than 10 ohms () per square meter (m2) of window area.

4. The method according to claim 1, wherein the retrofitted transparent window is electrically powered by a further voltage supply device by applying a heating voltage to the transparent window.

5. The method according to claim 4, wherein the further voltage supply device is a battery provided in a vehicle interior.

6. The method according to claim 4, wherein the further voltage supply device is provided in an interior of a vehicle.

7. The method according to claim 5, wherein the further voltage supply device is provided under the vehicle and not under a vehicle hood.

8. The method according to claim 5, wherein the further voltage supply device is independent from other voltage supply devices provided to apply a power to other powered functionalities of the vehicle.

9. The method according to claim 1, wherein the window is a laminated transparent window comprising an exterior face and an interior face.

10. The method according to claim 1, wherein a window temperature is measured by the at least one temperature sensor, the at least one temperature sensor being positioned inside the transparent window or in an interior face of the transparent window (face 4).

11. The method according to claim 1, wherein the window further comprises a switch element positioned inside the transparent window or in an interior face of the transparent window (face 4) to switch on/switch off the applying of a heating voltage to the transparent window.

12. The method according to claim 3, wherein the lower temperature threshold value is less than or equal to 4 C.

13. The method according to claim 1, wherein an upper temperature threshold value is in a range from 20 C. to 90 C.

14. The method according to claim 3, wherein the de-icing and/or de-fogging of the transparent window is monitored remotely or automatically activated when the transparent window temperature is below 0 C.

15. A window arrangement, which comprises: a. a transparent window with an electric heating device which is connected to at least two electrodes provided for connection to a voltage supply device such that by applying a heating voltage, a heating current flows through the electric heating device formed between the electrodes, b. at least one temperature sensor for measuring a window temperature, and c. a control device coupled with the at least one temperature sensor and the voltage supply device, which is suitably configured to carry out the method according to claim 1.

16. A window arrangement according to claim 15, wherein the retrofitted transparent window is a windshield comprising two glass sheets provided with, as the electric heating device, a heated coated film laminated between the two glass sheets and with power supplied through at least two busbars.

17. The window arrangement according to claim 16, wherein the at least one temperature sensor for measuring a window temperature is provided on an internal face of a window edge arrangement.

18. A method according to claim 1, wherein the transparent window is a vehicle windshield.

19. A method according to claim 1, wherein the electric heating device is a heating layer.

Description

[0032] The invention is now explained in detail using exemplary embodiments

[0033] According to one embodiment of the present invention, the window arrangement includes a transparent windshield of a motor vehicle, preferably of an electric motor vehicle, which is implemented, for example, as a composite window.

[0034] According to one embodiment of the present invention, the windshield has a rigid outer pane and a rigid inner pane, which are both implemented as individual panes and are fixedly bonded to each other via a thermoplastic adhesive layer. The two individual panes are approximately the same size, have a roughly trapezoidal curved contour, with the understanding that the invention is not restricted to this, but rather that the windshield can have any other shape suited for the practical application. The two individual panes are made of a glass material, such as float glass, cast glass, or ceramic glass or a non-glass material, for example, plastic, in particular polystyrene (PS), polyamide (PA), polyester (PE), polyvinyl chloride (PVC), polycarbonate (PC), polymethyl methacrylate (PMA), or polyethylene terephthalate (PET). In general, any material with sufficient chemical resistance, suitable shape and size stability, as well as adequate optical transparency can be used. Plastic, in particular based on polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and polyurethane (PU), can, for example, be used as an adhesive layer for bonding the two individual panes. For an application other than as a windshield, it would also be possible to produce the two individual panes from a flexible material. This kind of windshield are well-known and commonly used today.

[0035] The contour of the windshield is defined by a circumferential window edge, which is composed corresponding to the trapezoidal shape of two long window edges (top and bottom in the installation position) and two short window edges (left and right in the installation position).

[0036] According to one embodiment, a transparent heating layer serving for electric heating of the windshield is deposited on the side of the inner pane 4 bonded to the adhesive layer (side 3). The heating layer is applied substantially on the entire surface of the inner pane, with an edge strip of the inner pane circumferential on all sides not coated such that a heating layer edge is set back inward relative to the window edge.

[0037] According to one preferred embodiment, the heating layer is not applied on the inner pane 4, but instead to apply it on a large-area carrier, which is subsequently adhered to the individual panes and laminated between the 2 panes of glass. Such a carrier can, in particular, be a plastic film, made for example of polyamide (PA), polyurethane (PU), polyvinyl chloride (PVC), polycarbonate (PC), polyester (PE), or polyvinyl butyral (PVB) . . .

[0038] The heating layer includes an electrically conductive material. Examples of this are metals with high electrical conductivity such as silver, copper, gold, aluminum, or molybdenum, metal alloys such as silver alloyed with palladium, as well as transparent, conductive oxides (TCOs). TCOs are preferably indium tin oxide, fluoride-doped tin dioxide, aluminum-doped tin dioxide, gallium-doped tin dioxide, boron-doped tin dioxide, tin zinc oxide, or antimony-doped tin oxide. The heating layer 7 can consist of one conductive individual layer or a layer structure that includes at least one conductive sublayer. For example, such a layer structure includes at least one conductive sublayer, preferably silver (Ag), and other sublayers, such as anti-reflection and blocker layers.

[0039] The thickness of the heating layer can vary widely, with the thickness at every point being, for example, in the range from 30 nm to 100 um. In the case of TCOs, the thickness is, for example, in the range from 100 nm to 1.5 m, preferably in the range from 150 nm to 1 m, and even more preferably in the range from 200 nm to 500 nm. Advantageously, the heating layer has high thermal stability such that it withstands the temperatures of typically more than 600 C. necessary for the bending of glass without functional degradation. However, even a heating layer with low thermal stability, which is applied after the bending of the glass pane, can be provided. The sheet resistance of the heating layer is preferably less than 20 ohm and is, for example, in the range from 0.1 to 20 ohm. In the exemplary embodiment depicted, the sheet resistance of the heating layer is, for example, in the range from 1 to 5 ohm.

[0040] The heating layer is, for example, deposited from the gas phase, for which purpose methods known per se, such as chemical vapor deposition (CVD) or physical vapor deposition (PVD), can be used. Preferably, the heating layer is deposited by sputtering (magnetron cathode sputtering).

[0041] In one particular embodiment, the heating layer may be, conductive wires embedded into the adhesive layer bonder the two panes to form a heated wired windshield.

[0042] The windshield must be adequately transparent to visible light in the wavelength range from 350 nm to 800 nm, with the term transparency understood to mean light transmittance of more than 80%. This can be obtained, in particular, by means of individual panes made of glass and a transparent heating layer 7 made of silver (Ag).

[0043] The heating layer 7 is electrically connected to bus bars according to well-known technologies. Bus bars are made from the same material and can be produced, for example, by printing a silver printing paste onto the heating layer, for example, using a screen printing method. Alternatively, it would also be possible to produce the bus bars from narrow metal foil strips made, for example, of copper or aluminum. These can, for example, be fixed on the adhesive layer and disposed on the heating layer at the time of the bonding of the outer and inner pane. In this process, an electrical contact can be ensured through the action of heat and pressure at the time of the bonding of the individual panes forming the windshield.

[0044] The bus bar are connected via a connection line, which is, for example, implemented as a flat-band conductor (e.g., narrow metal foil), and a power line to one terminal (for example, negative terminal) of a voltage supply device to supply a feed voltage. By means of bus bars, a heating field is enclosed, in which upon application of a feed voltage, a heating current flows. The voltage supply device can be, for example, a battery or accumulator. Preferably, the voltage supply device is different than the motor vehicle battery, or a transformer coupled to a battery.

[0045] Preferably, the voltage supply device is provided inside the vehicle with an easy access. Thus, when the non-heated windshield originally installed on the vehicle has to be replaced, it could be replaced easily by a heated windshield to provide then a vehicle equipped with a heated (coated or wired) windshield. The bus bars of the retrofitted windshield may be then easily and quickly connected to the independent voltage supply device without modification of the vehicle battery. Thus, if the windshield is not well powered, only the voltage supply device dedicated to the windshield may be replaced reducing thus the cost and the impact on the other functionalities provided on the vehicle.

[0046] The battery may be different than the vehicle battery and may for example be installed inside the vehicle for example under the passenger se

[0047] Alternatively, the new retrofitted windshield may be connected directly to the vehicle battery.

[0048] Preferably, the voltage supply device is implemented such that a feed voltage between 30 to 60 volts, is made available, which can be the case, in particular with small batteries or batteries of electric vehicles.

[0049] According to the invention, the arrangement also has a temperature sensor. The at least one temperature sensor may be , disposed on the outward side of the outer pane (side 1) or preferably on the inward side of the inner pane (side 3), with it being, however, also conceivable for the at least one temperature sensor to be disposed between the two individual panes meaning laminated between the two individual panes. By means of at least one temperature sensor, the temperature of the windshield can be detected.

[0050] In another embodiment, the at least one temperature sensor may be disposed on the heating layer edge or window edge. Moreover, it is advantageous for the at least one temperature sensor to be disposed, in the window regions in which local overheating (hot spots) can occur. These are, in particular, heating-layer-free zones, for example, communication windows or end sections of separating lines for the structuring of the heating layer.

[0051] The at least one temperature sensor can be implemented in many ways, for example, as thermocouples/thermistors.

[0052] The at least one temperature sensor, may be connected for data transfer via a data line to a microprocessor-based control device. The control device is in one embodiment further connected via a data line to a switching device associated with the voltage supply device, which switching device is connected to power lines and serves to electrically connect the voltage supply device to the heating layer. It is likewise possible for the switching device to be integrated into the voltage supply device.

[0053] The data lines can be implemented with a wired or wireless connection. Thus a de-icing and/or de-fogging process for de-icing the window 2 is, in this case, activated or started manually by operating a switching element in a control console of the motor vehicle. It would also be conceivable to start the de-icing process automatically, for example, upon starting the engine and detection of a low outside temperature below a specified threshold value, for example, 0 C. or less, by means of at least one temperature sensor. A start signal can, for example, be generated manually or automatically to activate the de-icing and/or de-fogging process.

[0054] According to the invention, the start signal may be preferably generated through an application from a smart device such as phone, an external remote control device . . .

[0055] According to another embodiment, the start signal may be activated through a capacitive touch provided on the transparent window and particularly a windshield. This is particularly interesting when the windshield is a heated coated windshield wherein a capacitive touch function may be provided. Such as capacitive touch are described in the following patent references: WO2013189794, WO2013189796 . . .

[0056] If a de-icing process has been activated, the temperature of the windshield is still measured before the initial application of a heating voltage to the heating layer. If the temperature of the windshield on only one temperature sensor exceeds a selectable lower temperature threshold value, here, for example, 0 C. or less, no heating voltage is applied to the heating layer and the method or de-icing/de-fogging process is terminated. For this purpose, a stop signal can, for example, be generated. The window arrangement then transitions into a standby or OFF state. If, alternatively, the temperature of the windshield equals or is less than the lower temperature threshold value, here, for example, 0 C. or less, the feed voltage comprised between 30 nand 60 volts, supplied by the voltage supply device is applied to the heating layer for a period defined by the de-icing and/or de-fogging speeds.

[0057] Then, if the temperature of the windshield measured by the at least one temperature sensor corresponds to a selectable upper temperature threshold value, here, for example, in a range from 20 C. and 90 C. or for example 70 C., the de-icing and/or de-fogging process is terminated. For this purpose, a stop signal can, for example, be generated. The window arrangement then transitions into a standby or OFF state. As already stated, preferably, a heating voltage between 30 to 60 volts, is applied to the heating layer for a till the temperature of the windshield measured by the at least one temperature sensor corresponds to a selectable upper temperature threshold value, here, for example, in a range from 20 C. and 90 C. or for example 70 C., as a result of which de-icing and/or de-fogging of the windshield can be obtained with a low electric power loss. Preferably, the heating voltage and the heating period are selected such that a heating power corresponding to a resistance less than 10 ohms () per square meter (m.sup.2) of window area is generated..