Method for manufacturing a vehicle rear window with an integrated heater antenna

Abstract

The manufacturing process for a vehicle rear window (1) includes the following steps: preparing a glass plate (2) having an outer surface suitable for being directed toward the exterior of the vehicle and an inner surface suitable for being directed toward the interior of the vehicle, providing a heater (H) on the inner side of the glass plate (2) that includes two bus bars (3) electrically connected to the positive and negative poles of the vehicle battery, respectively, and a plurality of horizontal heating lines (4) connected to the bus bars (3), and applying an antenna trace (A) on the inner side of the glass plate (2) that includes a strip of transparent nanowires made of a conductive material. The step of preparing the antenna trace (A) is made by spray coating the inner side of the glass plate (2).

Description

Technical Field

[0001] The present invention relates to the field of automobiles, and more particularly, to a method for manufacturing a rear window provided with an integrated heater antenna.

Background Art

[0002] Heaters are used in the field of automobiles to remove frost and fog on the rear windows of vehicles. Vehicle antennas are realized by rear window manufacturers who make heaters using the same technology. Such technology consists of realizing a grid of lines printed with a conductive screen based on copper or silver on a glass plate according to a mask. The screen-printed glass plate is annealed and tempered in an oven to ensure the curing and strength of the above screen-printed plate.

[0003] To remove frost and fog on the rear window provided with a heater, a battery voltage is applied between two electrodes (rheophores) of busbars arranged at the right and left ends of the rear window. The busbars are connected to conductive wires that horizontally cross the rear window from right to left.

[0004] For the application of voltage, current flows from the busbar connected to the anode of the battery to the heater towards another busbar connected to the cathode, and is divided in parallel to each of the horizontal lines of the heater coupled to the busbar. As the current flows through each horizontal branch of the heater, the current heats the inside of the glass to remove the frost on the glass. The uniformity and rapidity of fog removal depend on the uniformity of the voltage drop along each horizontal line of the heater between the busbar connected to the anode of the battery and the busbar connected to the cathode of the battery.

[0005] Generally, rear window manufacturers design the heater layout to optimally distribute current to all horizontal lines of the heater, and to distribute the current as uniformly as possible within each line, while at the same time striving to minimize costs by reducing the number of screen-printed heating lines required for defogging.

[0006] The glass manufacturer provides elements used for defrosting glass and elements used for antennas, using the same screen-printed masks as those used for heaters.

[0007] The operating elements for the antenna include the following: - Vertical or slightly angled screen printing that intersects the heater's horizontal line entirely or partially. Screen printing is used to optimize antenna performance by improving bandwidth or impedance matching. The maximum angle is limited and enforced by the glass manufacturer so as not to deviate from the distribution of heating current from the path, thereby impairing the uniformity of the defrosting action. Such limitations become a performance limiting factor with regard to the design of antenna systems integrated into the rear window of a vehicle. Larger line angles result in the antenna having impedance matching over a wider bandwidth, thereby resulting in a more uniform receivable range at the frequencies of the target band. - Screen printing for antenna power supply. This screen printing includes a copper single-pole terminal with a welded pad for interconnection at one end and a connector for connection to an amplifier.

[0008] Regarding operation, the screen print for antenna power supply can be of various types: - Screen printing coupled to a heater. This acts as an electric field probe, acquiring a useful received signal captured by the heater by conduction or radiation. Screen printing directly coupled to a heater is known, where it is physically connected to the heater on the opposite side of the pad. Similarly, screen printing capacitively coupled to a heater is known. Screen printing for capacitive coupling is not directly connected to the heater, and a screen printing section is provided at the end opposite to the pad. The screen printing section faces the nearest heating line (typically at a distance of 3-15 mm) and is unfolded parallel to it to obtain capacitive coupling. - Isolated screen printing that operates by reverberation without using a heater coupling. Similarly, isolated screen printing has a pad and a copper wire with terminals for connecting to an amplifier. - Screen printing of a stub. This can be connected directly to the heater or positioned near the heater. However, it does not have pads for interconnecting with an amplifier. Screen printing of stubs is used to optimize antenna performance by improving bandwidth or impedance matching.

[0009] Currently, there are two types of constraints on integrating the screen printing of the antenna onto the rear window of a vehicle:

[0010] Constraints of functional frost removal Screen printing of an antenna directly connected to a heater can only be achieved by a responsive, uninterrupted contact with the heater, as in the case of direct coupling.

[0011] For extended lines that intersect with defrosting lines, their inclination must have a limited value. They can be perfectly perpendicular to the vertical line or slightly inclined. This is because they must intersect the horizontal line only at points of equipotential. Otherwise, the current flowing along the intersection will be additionally divided in response to the intersection, reducing the strength of the current flowing along the horizontal line. This results in a lack of uniformity and a reduced effect on defrosting the glass in the longitudinal direction. Free inclination of lines intersecting the heating line results in more uniform performance in the target band.

[0012] Furthermore, the need to maintain a uniform current distribution for removing frost from the glass limits the possibility of screen printing an antenna power supply with direct or capacitive coupling that can capture useful signals in areas other than those around the heater. Alternatively, if the useful signals captured by the heater are concentrated in the inner part of the heater, it is currently impossible to reach such areas by tracing a screen printing of an antenna power supply that can be coupled near points of higher electric field strength. This reduces the effectiveness of antennas integrated into the rear window and impairs the freedom in optimizing the layout to improve performance.

[0013] Constraints on ion movement This phenomenon occurs in response to capacitive coupling between the screen printing of the antenna power supply and the screen printing of the heater when power is supplied to the heater and the potential difference becomes significant, or when the distance between the screen printings is too short. The actual effect of ion transfer occurs when moisture, condensation, or impurities (dust, metal dust, etc.) are present on the glass surface. The actual effect of ion transfer is that a current flows from the horizontal line of the heater, thereby transferring energy to the screen printing of the antenna power supply with capacitive coupling at a potential difference from zero. The current density is so strong that the Joule effect causes overheating of the antenna trace, dissipating the antenna trace and subsequently causing the screen-printed layout on the glass to break. To mitigate such defects, a minimum safety distance is now imposed on capacitive coupling. It varies from 8 to 18 mm depending on the specific case and by the automotive manufacturer, far exceeding the processing limitations of glass manufacturers that can produce screen printings at distances of less than 5 mm, improving the effectiveness of capacitive coupling and the strength of the captured signal.

[0014] Constraints of functional vision The layout of heated screen printing is evaluated in terms of its visual impact on the vehicle driver. Such layouts must be designed so that the lines do not obstruct the rearward view of obstacles encountered while driving. Generally, car manufacturers tend to leave the central part of the rear window open and avoid placing lines in the center of the glass or around the central area of ​​the glass.

[0015] Aesthetic constraints Because it is visible from the outside, automobile manufacturers consider the rear window of a vehicle as an aesthetic component that must be approved by the design department. In detail, the design of the rear window lines must conform to aesthetic rules, and automobile manufacturers sometimes modify the layout of the antenna trace even if the antenna system functions well in terms of signal reception. Typically, for aesthetic reasons, the antenna design is restricted in terms of the number of vertical lines and the shape of the antenna power supply trace. In detail, the antenna power supply trace must be adapted to the rear window according to the shape of the heater. Currently, to mitigate the aesthetic impact caused by the presence of the antenna trace, the antenna trace is hidden in a black band area, i.e., the peripheral area of ​​the glass. The black band area is internally defined by the transparent portion in the center of the glass and externally defined by the adhesive area between the rear window and the body of the vehicle door. The trace is deposited in the black band, which has a covering effect so that it is not visible from the outside. However, this is not always possible, depending on the type of vehicle, as the rear window is not specially extended vertically, and therefore the black band becomes very narrow. In such cases, the available space for antenna tracing is very small, making it impossible to connect the screen printing for antenna power supply to the central line inside the heater, resulting in a complex design and compromised performance.

[0016] U.S. Patent No. 5,952,977 discloses a solution to improve rearward visibility through the rear window, which is impaired by the use of vertical lines positioned in the central region of the glass. While such vertical lines provide good performance in terms of reception, they reduce rearward visibility and are positioned precisely in the driver's visual trajectory. To solve this problem and maintain a high level of performance, U.S. Patent No. 5,952,977 proposes a system with two vertical lines positioned on the sides of the central region of the rear window. These two vertical lines intersect all horizontal heating lines, extend at the top of the heaters, and form a "T" coupled with capacitive coupling using screen printing for antenna power supply. Each vertical line is connected to a pad and a single-pole wire, either toward a receiver or toward an amplifier positioned in the middle. Several variations of the above capacitive coupling between the heater vertical lines and the screen printing for antenna power supply are proposed. However, even if the central area of ​​the rear window is advantageously left open and rearward visibility is improved, such solutions are compromised with negative aesthetic effects due to the complexity of the power supply lines and capacitive coupling. This is particularly problematic for automotive manufacturers and implies some limitations on possible applications. Another drawback arises when a small rear window is applied, where the non-heated area between the periphery of the rear window and the area for bonding / overlapping with the metal door / body is small. In this case, there is not enough space available for the aforementioned coupling.

[0017] European Patent No. 1502321 discloses an antenna trace layout in a heater comprising a set of vertical sections arranged in a step pattern perpendicular to horizontal heating lines. Each vertical section is in contact with a pair of horizontal heating lines. Advantageously, a more direct radiation diagram can be obtained from these solutions due to a special distribution of signal current useful for radio reception. This radio reception is derived from the array of vertical sections without altering the distribution of heating current for removing fogging and frost from the rear window. This is because the vertical sections of the antenna connect a pair of horizontal lines between two equipotential points, thereby allowing the DC with heating function to flow along each horizontal line and not through the vertical sections. Such a solution is compromised by providing multiple vertical sections distributed across the width and height of the heater, including the central region of the rear window. As a result, the effects of the above vertical sections may be dangerous to the driver in terms of rearward visibility compared to the presence of two conventionally simple, continuous vertical lines arranged in the central region of the rear window. Furthermore, the aesthetic impact of the heater's step pattern, which is more irregular than conventional designs, is not understood by automotive manufacturers who tend to prefer obvious, simple, and regular shapes and patterns.

[0018] U.S. Patent No. 9,231,213 discloses a system that provides integration of electrical components, antennas, and RF circuits onto a single transparent platform (glass). A spray-coated film of silver nanowires (AgNWs) is used as a transparent conductive film to realize antennas or the interconnection of passive elements such as resistors, capacitors, and inducers. Furthermore, graphene is used as an active channel for realizing RF devices (switches, amplifiers, etc.). In addition, a method called a “locally selective conductor control method” is imposed, which provides controlled deposition of nanomaterial layers in areas where higher conductivity inevitably results in loss of transparency. The antenna is a separate element and is not integrated with the heater. The antenna layout is general and does not have any particular elements (such as slot antennas with coplanar structures and power supply). For the dielectric layer of capacitors, deposition of materials such as SiNX (silicon nitride) or HfO2 (hafnium oxide) is considered. Oxide deposition techniques are not described.

[0019] U.S. Patent Application Publication No. 2016 / 0134008 discloses a rear window for a vehicle that includes a mesh grid obtained by depositing transparent conductive nanowires (AgNW, ITO, CNT) onto a glass plate. Such a grid can be part of an antenna or heating element. The deposition of transparent nanowire grids is a complex process. U.S. Patent Application Publication No. 2016 / 0134008 proposes using a transparent adhesive layer to separate two conductive traces at different levels. Furthermore, the application of the adhesive layer is inaccurate and complex. [Prior art documents] [Patent Documents]

[0020] [Patent Document 1] U.S. Patent No. 5952977 [Patent Document 2] European Patent No. 1502321 [Patent Document 3] U.S. Patent No. 9,231,213 [Patent Document 4] U.S. Patent Application Publication No. 2016 / 0134008 [Summary of the Invention] [Problems to be Solved by the Invention]

[0021] An object of the present invention is to disclose a manufacturing process of a rear window provided with a heater-integrated antenna, in which the screen printing of the antenna is transparent and does not impair the aesthetics of the rear window and the visibility of the driver, thereby eliminating the drawbacks of the prior art.

[0022] Another object is to disclose a manufacturing process of a rear window in which the antenna has high performance with respect to bandwidth and impedance and does not interfere with the effectiveness of the heater integrated into the rear window at the same time. [Means for Solving the Problems]

[0023] These objects are achieved by the present invention with the features of independent claim 1.

[0024] Advantageous forms of the present invention will become apparent from the dependent claims.

[0025] In view of the above, in order to overcome the limitations of the prior art and the design and performance constraints of the rear window integrated antenna, it is desirable to apply the following conditions. 1. The screen printing added to the heater that operates as an antenna should be transparent and invisible so as not to affect aesthetics and vision regardless of the size of the rear window and the size of the available space without the heater lines. 2. The screen printing for antenna coupling and power supply should be used adjacent to the inner and central regions of the heater so as not to come into electrical contact with the heater layout, thus avoiding changing the distribution of the current required to remove the frost on the glass, and it is desirable to separate it so as to block the region of the stronger electric field of the received signal. 3. It is desirable to have a high-impedance DC vertical line to prevent the current used for defrosting from diverting from the normal path along the horizontal heating line, in order to enjoy a greater degree of freedom regarding the outline of the screen printing of the antenna that intersects the horizontal heating line.

[0026] These results can be obtained by depositing an electrically insulating dielectric layer on the inside of the rear window. Conductive lines made of nanomaterials (copper, silver, and carbon-based nanomaterials) are then deposited on top of it. They act as antennas and are invisible because they are more intrinsically transparent.

[0027] Several nanomaterials can be considered for realizing transparent antenna traces. Examples include silver nanowires (AgNWs), copper nanowires (CuNWs), PEDOT:PSS, and carbon nanotubes (CNTs). These nanomaterials can be deposited by realizing transparent conductive films using various techniques such as drop melting, Meyer rod coating, vacuum filtration, spin coating, and spray coating. Spray coating is preferred because it is adaptable, feasible on a large scale, and inexpensive.

[0028] The deposition solution is obtained using a suitable process according to the material used. For example, referring to silver nanowires (AgNW), 1 g of AgNW solution is diluted with 14 g of isopropyl alcohol and 5 g of deionized water (DI), and then stirred. Similarly, 1 g of PEDOT:PSS is diluted with 4 g of DI water.

[0029] Subsequently, 10 mg of Dynol 604 and 200 mg of ethylene glycol (EG) are added to improve conductivity. Next, this solution is treated with ultrasound for 30 seconds to disperse the clumps.

[0030] The CNT-based solution consists of DI water, 90% semiconductor CNTs, and sodium dodecyl sulfate (SDS) acting as a dispersant. 1% by weight of SDS is dissolved in DI water, and 0.03% by weight of CNTs is added. This solution is treated in an ultrasonic machine at 50% power for 25 minutes, then centrifuged at 15krpm for 90 minutes, and 80% of the supernatant is separated for use as CNT ink.

[0031] To create the copper nanowire ink, 300 mg of copper hydrochloride is immersed in 25 g of distilled water and ultrasonically treated for 5 minutes. Next, 900 mg of oleylamine is added, and this solution is ultrasonically treated at 200 W for 60 beats.

[0032] Next, 300 mg of L-ascorbic acid dissolved in 5 g of DI water is added. This solution is then placed in a silicone oil bath at a calibrated temperature of 81°C for 12 hours.

[0033] Referring to Figure 1, spray coating technology enables the creation of thin, reproducible, homogeneous, large-scale feasible, inexpensive, and low-substrate temperature films using a fully automated system. Such a system comprises a spray nozzle (N) and a heated plate (P) on which a substrate (S) is positioned. This spray coating technology requires the simultaneous control of several parameters, including spray pressure, flow rate, scanning speed, height (distance between the nozzle and the substrate (D)), and substrate (S) temperature. Specific forms of the sprayed material can be achieved by using a mask (of plastic or metal) that covers the parts of the substrate where the material is not deposited, but not the parts where the functional layer is deposited.

[0034] Advantageously, to further enhance the hydrophilicity of the substrate surface and improve wetting properties and film formation on the active substrate, an oxygen and plasma cleaning treatment can be performed before spray coating the substrate (S). The cleaning treatment time varies depending on the type of material. If the passive substrate is glass, the oxygen plasma cleaning treatment is performed for 1 minute.

[0035] Figure 2 shows the microstructure of silver nanowires (AgNW) deposited in five layers on a substrate (S).

[0036] Figure 3 shows the transmittance of AgNW film with respect to the number of layers.

[0037] Figure 4(A) shows the synthesis solution of copper nanowires (CuNW). Figures 4(b) and 4(c) are SEM images of copper nanowires at low and high magnification. Figure 4(D) is a binary image conversion for determining the diameter of a single wire in the copper nanowire layer. Figure 4E shows the transmittance spectrum of the CuNW film as the wire density increases.

[0038] The advantage of this process lies in the possibility of controlling the thickness of the deposited elements as an addition to a previously deposited thin layer. Given that the optical absorption of thin films increases exponentially with thickness (Lambert-Beer's law), precise control of thickness is crucial for obtaining a translucent layer. Furthermore, this approach improves sample reproducibility because the formation of deposited elements is carried out in multiple identical operations, reducing the generation of impurities during individual deposition operations. The substrate temperature was 50°C, the atomizing pressure at the spray nozzle was 0.05 MPa, the dispersion pressure sprayed onto the passive substrate was 0.02 MPa, the deposition rate was 250 mm / s, and the distance (D) between the nozzle and the substrate was 3 mm.

[0039] Given its versatility, spray coating technology can also be used to obtain insulating layers. Insulating transparent polymers, such as polymethyl methacrylate (PMMA), dissolved in solutions and sol-gel forms of metal oxides (most commonly aluminum oxide and titanium oxide sol-gels), can be atomized and deposited using the spray coating technology described above. The realization of thin layers made from these materials, characterized by their transparency and low conductivity, allows for the isolation of several metal layers and prevents unwanted contact.

[0040] After deposition of each material, the substrate must be subjected to heat treatment or optical treatment (UV pulsed light or IR light) to cause evaporation of the solvent and dissolution of the dispersed material (in the case of metal nanowires), realization of better polymer chains (in the case of conductive insulating polymers), or drying of the gel (in the case of sol-gels).

[0041] As described above, the rear window is realized by sequentially depositing various functional materials using a suitable mask. In detail, the process includes the following steps. 1. Step of preparing printing ink with transparent nanowires. 2. Steps to prepare the transparent dielectric substrate (cleaning, and plasma activation if applicable). 3. The step of positioning and aligning the screen printing mask. 4. The step of spray coating with printing ink. 5. A step of performing thermal or optical post-treatment on the substrate.

[0042] These steps are repeated for all materials. In the case of integrating the heating line with a dedicated conductive line for the antenna, the entire process is repeated at least three times. In detail, the process is as follows: a. Steps 1 to 5 for deposition of conductive heating lines (thickness of 30 nm to 500 nm depending on the nanomaterial used and transparency level). b. Steps 1 to 5 for the deposition of electrical insulating material (thickness of 100 nm to 10 microns, depending on the nanomaterial used and the level of transparency). c. Steps 1 to 5 for depositing conductive lines for the antenna. The materials used in these steps do not need to be the same as those used in step a (the choice of material and thickness is determined by the desired impedance).

[0043] The aforementioned technology can be applied to the rear window of a vehicle to obtain a heater-integrated antenna. The overall result is a rear window-integrated antenna system, which is the same as a conventional system. However, the rear window of the present invention overcomes the limitations of conventional rear windows because it has zero aesthetic impact on the antenna line and offers greater versatility at the design stage. This is because it enables electromagnetic coupling of the antenna trace in the area further inside the heater, as well as external shapes and solutions that were not permitted in the so-called conventional technology.

[0044] New types of coupling and screen printing for antenna areas: - Direct connection with horizontal lines other than the first line at the top or the last line at the bottom. - Capacitive coupling with horizontal lines other than the first line at the top or the last line at the bottom. - Capacitive coupling between the heater line and the more closely located horizontal line. The presence of oxide deposits typically electrically insulates the proximal coupling, which is subject to ion transfer. - A new overlapping capacitive coupling. Instead of being identical to the heater surface, the screen printing for the antenna power supply can be overlapped at the same height as the heating screen printing, and capacitive coupling can be achieved transversely solely by the presence of an oxide layer in the intermediate position, with almost no gaps, thus creating a large-strength capacitive coupling. - Newly extended direct bonding. By using the deposition of nanowires with controlled high impedance values, an extended direct bonding bandwidth is created instead of delay-free bonding (with an even more limited bandwidth). - High impedance crossing screen printing with a high tilt value relative to the vertical and lower interference with the current path imposed on the horizontal heating line. -Screen printing of antenna power supplies with direct coupling or capacitive coupling. This comprises a concentrated planar structure obtained by spray coating of transparent copper nanowires (or silver nanowires) and an oxide layer which is an insulator to obtain a capacitive or dielectric element, depending on the specific requirements of the impedance adapter at the desired frequency. - Stud-compatible screen printing that can be applied to horizontal lines other than the first line at the top or the last line at the bottom. - An antenna system layout that takes into account transparency introduced by nanowires used for tracing, with a greater number of vertical lines in a more central position on the rear window, which is not possible with the current system. - The possibility of extending the transparency of screen printing to the heating lines to significantly improve the driver's rearward visibility.

[0045] Further features of the present invention will become more apparent from the following detailed description with reference to the illustrative and non-limiting embodiments shown in the accompanying figures. [Brief explanation of the drawing]

[0046] [Figure 1] This is a diagram of a nozzle for depositing nanowires. [Figure 2] This is an image of AgNW deposited in five layers on a substrate. [Figure 3] This shows the transmittance of AgNW film based on the number of layers. [Figure 4] (A) is a photograph of the synthesis solution of copper nanowires, (b) is a SEM image of copper nanowires at low magnification, (c) is a SEM image of copper nanowires at high magnification, and (d) is a conversion of the binary image. [Figure 4E] This shows the transmittance spectrum of a CuNW film obtained by increasing the wire density. [Figure 5] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 6] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 7] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 8] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 9] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 9A] This is a detailed cross-sectional view of Figure 9. [Figure 10] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 10A] This is a detailed cross-sectional view of Figure 10. [Figure 11] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 12] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 13] This figure shows a possible embodiment of the rear window according to the present invention. [Figure 13A] This is a diagram showing an embodiment of a flat-fitting structure. [Figure 13B] This is a diagram showing an embodiment of a flat-fitting structure. [Figure 13C] This is a diagram showing an embodiment of a flat-fitting structure. [Figure 14] This figure shows a possible embodiment of the rear window according to the present invention. [Modes for carrying out the invention]

[0047] Referring to Figures 5 to 14, the rear window of the present invention is disclosed, which is generally shown by reference numeral (1).

[0048] In the following explanation, "horizontal" and "vertical" refer to the arrangement of lines in the diagram.

[0049] Referring to Figure 5, the rear window (1) comprises a glass plate (2) that is substantially rectangular and has dimensions suitable for covering the rear of the vehicle body.

[0050] For illustrative purposes, the glass plate (2) can be a tapered multilayer or single-layer glass with a thickness of approximately 5 to 8 mm.

[0051] The outer side of the glass plate (2) is preferably directed toward the exterior of the vehicle, and the inner side of the glass plate (2) is preferably directed toward the interior of the vehicle.

[0052] The heater (H) is applied to the inside of the glass plate (2).

[0053] The heater (H) comprises two busbars (3) made of conductive material, which are arranged vertically near the lateral edge of the glass plate. Each busbar (3) is electrically connected to the anode and cathode of the vehicle's battery, respectively, to define a potential difference between the two busbars (3).

[0054] The busbar (3) can be made by conventional means by screen printing a copper or silver conductive paste onto a glass plate (2).

[0055] Advantageously, to obtain transparent busbars, the busbars (3) can be obtained by spray-coating transparent nanowires onto the glass plate (2) as shown above. For illustrative purposes, each busbar (3) is obtained by depositing three layers of nanowires and has a width of 6-30 mm, an extension of 20-100 cm, and a thickness of 30-50 nm.

[0056] The busbar (3) is connected by multiple horizontal heating lines (4). For example, 16 horizontal heating lines can be arranged in parallel at equal intervals.

[0057] The horizontal heating line (4) can be made by conventional means by screen printing a copper or silver conductive paste onto a glass plate (2).

[0058] Advantageously, to obtain a transparent horizontal heating line, the horizontal heating line (4) can be obtained by spray-coating transparent nanowires onto the glass plate (2) as shown above. For illustrative purposes, each horizontal heating line (4) has a width of 1 mm, an extension of 80 mm, and a thickness of 10-20 nm, obtained by depositing a single layer of nanowires.

[0059] The application of a potential difference between the two busbars (3) generates a current circulation in the horizontal heating line (4), which is heated and removes frost from the rear window.

[0060] The rear window (1) is provided with an antenna trace (A) (shown as a dashed line in the figure) applied to the inside of a glass plate (2). According to the present invention, the antenna trace (A) is obtained by spray-coating transparent nanowires onto the glass plate (2) as shown above.

[0061] In Figure 5, the antenna trace (A) includes an intersecting trace (5) and a separating trace (6).

[0062] The crossing trace (5) intersects with the horizontal heating line (4). The crossing trace (5) is perpendicular to the horizontal heating line (4) and intersects with all horizontal heating lines.

[0063] The separation trace (6) is positioned inside the glass plate (2) above the heater (H) and forms a pattern, for example, an "S" shape (60), with vertical traces (61) intersecting this "S" shape (60).

[0064] One end of the separation trace (6) is connected to a pad (7) applied to the side of the glass plate that is not normally exposed to the external environment. The pad (7) can be made of transparent nanowires.

[0065] The pad (7) is electrically connected to an electronic component, such as an amplifier or impedance adapter, which consists of a chip crimped or bonded to the pad (7).

[0066] The crossed trace (5) and separated trace (6) are obtained by spray coating of transparent nanowires. The crossed trace (5) intersects with the horizontal heating line (4), but it should be considered that this does not pose a problem for the nanowire spray coating.

[0067] It should be considered that the crossed trace (5) has a width of 1 mm, a thickness of 5 to 10 nm, and an extension of 20 to 100 cm. This crossed trace (5) can be obtained by the nozzle (N) disclosed in Figure 1.

[0068] The separation trace (6) can be easily obtained using the nozzle (N) shown in Figure 1.

[0069] Figure 6 shows an example in which the antenna trace (A) includes a direct-coupled trace (8) located on a plate (2) above the heater, in addition to the cross-trace (5). The first direct-coupled trace (8) is connected to the pad (7) and the busbar (3). The second direct-coupled trace (8) is connected to the pad (7) and to a horizontal heating line (4), such as the highest horizontal heating line.

[0070] The pad (7) is located in the upper inner region of the plate and is suitable for electrically connecting to electronic components.

[0071] In this case as well, the directly bonded trace (8) is obtained by directly spray-coating transparent nanowires onto the plate (2). The width and thickness of the directly bonded trace (8) are the same as those of the crossed trace (5) and the separated trace (6).

[0072] Figure 7 shows an example of a rear window with a directly coupled cross trace (80) in which an antenna trace (A) is connected to a pad (7) disposed on a plate (2) outside the heater and intersects with one or more horizontal heating lines (4). Advantageously, the directly coupled cross trace (80) intersects the horizontal heating lines (4) at an angle other than 90°, for example, 60–80°.

[0073] The intersecting direct coupling traces (80) are realized using transparent nanowire technology. Transparent nanowire technology enables a wide direct coupling bandwidth because transparent nanowires have controlled impedance values ​​so that the current flow, which must flow only along the horizontal heating line (4), does not deviate.

[0074] Figure 8 shows an example in which, in addition to the crossing trace (5), the antenna trace (A) is located parallel to the highest horizontal heating line (4) and includes a capacitive coupling trace (9) positioned inside the plate (2) above the heater. The capacitive coupling (9) is connected to a pad (7) located in the upper region inside the plate and is suitable for electrical connection to electronic components such as amplifiers or impedance adapters.

[0075] In this case as well, the capacitively coupled traces (9) are obtained by directly spray-coating transparent nanowires onto the plate (2), and their width and thickness are the same as those of the directly coupled traces (8, 80) of the crossed traces (5) and separated traces (6).

[0076] By using a spray coating technique for transparent nanowires, the capacitive coupling trace (9) can be positioned very close to the horizontal heating line (4), for example, at a distance of less than 8 mm, preferably less than 5 mm, and it should be considered that better capacitive coupling can be obtained compared to the conventional technique where the capacitive coupling trace is at a distance greater than 8 mm from the horizontal heating line.

[0077] Referring to Figures 9 and 9A, the capacitive coupling trace (9) can be advantageously obtained by spray-coating transparent nanowires onto a transparent oxide layer (10) (shown in gray in Figure 9) disposed inside the glass plate (2).

[0078] The transparent oxide layer (10) is deposited on the horizontal heating line (4). As shown in Figure 9A, a horizontal gap (d) of less than 8 mm, preferably less than 5 mm, is provided between the capacitive coupling trace (9) and the horizontal heating line (4) in cross-section.

[0079] The capacitive coupling traces (9) are staggered so as to define a horizontal gap (d) between the axis of the horizontal heating line (4) and the axis of the capacitive coupling traces (9) with respect to the horizontal heating line (4) on which a transparent oxide layer (10) is applied. The horizontal gap (d) is less than 5 mm, and the transparent oxide layer (10) has a thickness of less than 5 mm.

[0080] The transparent oxide layer (10) prevents ion transfer between the capacitive coupling trace (9) and the horizontal heating line (4).

[0081] Figure 9 shows a capacitive coupling trace (109) positioned parallel to the busbar (3) on the transparent oxide layer (10). In this case, the transparent oxide layer (10) is L-shaped. The capacitive coupling trace (109) near the busbar is connected to a capacitive coupling trace (9) that provides coupling to the horizontal heating line (4).

[0082] Figures 10 and 10A show an example in which a capacitive coupling trace (9) is obtained by spray coating a transparent oxide layer (10) and is positioned in an overlapping location aligned with the horizontal heating line (4), i.e., positioned with zero horizontal voids in cross-section. Considering the above, the vertical void (s) is defined between the horizontal heating line (4) and the capacitive coupling line (9), equal to the thickness of the transparent oxide layer (10). Advantageously, the thickness of the transparent oxide layer (10) is less than 5 mm.

[0083] Such a solution ensures effective capacitance without any ion transfer between the capacitive coupling trace (9) and the horizontal heating line (4).

[0084] Figure 11 shows an internal capacitive coupling trace (209) located inside the heater (H) as a horizontal line between two horizontal heating lines (4). The internal capacitive coupling trace (209) is connected to a pad (7) located on the outer plate (2) of the heater by a connecting trace (105) that crosses the horizontal heating line (4).

[0085] The rear window (1) also has vertically positioned electrostatic internal traces (309) which cross multiple horizontal heating lines and are coupled with intersecting traces (5).

[0086] The rear window (1) also includes the following: - An external stub (400) is positioned on the outer plate (2) of the heater and connected to the horizontal heating line (4). - An internal stub (401) is positioned on the inner plate (2) of the heater and connected to the horizontal heating lines (4) between the two horizontal heating lines (4).

[0087] Figure 12 shows a rear window that includes an oblique intersection line (50) in which the antenna trace (A) intersects multiple horizontal heating lines at an angle of, for example, 30 to 50°.

[0088] This diagonal crossing trace (50) is arranged by two fan-shaped configurations (V1, V2) with an origin (O) in the central section of the highest horizontal heating line (4).

[0089] The oblique cross traces (50) are implemented using high-impedance nanowires to prevent the current flow from deviating from the horizontal heating line (4).

[0090] Figure 13 shows an example of a rear window in which a connection trace (105) is connected to a capacitive coupling trace (109) and to a flat fitting structure (13) disposed on a plate (82) outside the heater. The flat fitting structure (13) is connected to a pad (7) disposed on a plate (2).

[0091] Figures 13A, 13B, and 13C show three examples of flat-fit structures. A flat-fit structure is a stub for a transformer or concentrated inductance and is capacitive.

[0092] The planar-fit structure (13) is obtained by spray coating with transparent nanowires.

[0093] Figure 14 shows an example of a rear window where the heater's horizontal heating line (4) is obtained by spray-coating transparent nanowires, and for this reason the horizontal heating line (4) is indicated by a dashed line.

[0094] Figures 5 to 14 show various examples of heaters with different types and layouts of antenna traces (A), but these types and layouts of antenna traces can be combined with each other.

Claims

1. A method for manufacturing a rear window (1) for a vehicle, comprising the steps of: Providing a glass plate (2) having an outer side suitable for installation facing the exterior of the vehicle and an inner side suitable for installation facing the interior of the vehicle; forming a heater (H) on the inside of the glass plate (2) having two bus bars (3) electrically connected to the positive and negative poles of the battery of the vehicle, respectively, and a number of horizontal heating lines (4) connected to the bus bars (3); forming a transparent antenna trace (A) having a strip of transparent nanowires on the inner side of the glass plate (2) on which the heater (H) is formed; The step of forming the transparent antenna trace (A) includes: Providing a transparent oxide; a step of subjecting the inner surface of the glass plate (2) on which the heater (H) is formed to a hydrophilic treatment by cleaning with oxygen and plasma; Positioning and forming a printing mask on the hydrophilized surface; spray-coating the transparent oxide onto the surface on which the printing mask is formed to form a transparent oxide layer (10); Providing a printing ink comprising transparent nanowires; Positioning and forming a printing mask on the surface on which the transparent oxide layer (10) is formed; spray-coating the printing ink on the surface on which the printing mask is formed to form a capacitive coupling trace (9) as a transparent antenna trace (A); and performing a thermal or optical post-treatment on the surface including said transparent oxide layer (10) and said transparent antenna trace (A), a portion of said transparent antenna trace (A) as a capacitive coupling trace (9) adjacent and parallel to said horizontal heating line (4) on the opposite side of said transparent oxide layer (10).

2. The capacitive coupling trace (9) overlaps the horizontal heating line (4) on which the transparent oxide layer (10) is applied such that a vertical gap (s) of thickness equal to the transparent oxide layer (10) is formed between the horizontal heating line (4) and the capacitive coupling trace (9), The method of claim 1, wherein the transparent oxide layer (10) has a thickness of less than 5 mm.

3. 2. The method of claim 1, wherein the capacitive coupling traces (9) are staggered with respect to the horizontal heating lines (4) on which the transparent oxide layer (10) is applied so as to ensure a horizontal gap (d) between an axis of the horizontal heating lines (4) and an axis of the capacitive coupling traces (9), the horizontal gap (d) being less than 5 mm and the thickness of the transparent oxide layer (10) being less than 5 mm.

4. The method according to any one of claims 1 to 3, wherein the busbars (3) and the horizontal heating lines (4) of the heater are obtained by spray-coating, on the side of the glass plate (2), strips of transparent nanowires made of a conductive material.

5. The method of any one of claims 1 to 4, wherein the transparent nanowires comprise silver nanowires (AgNWs), copper nanowires (CuNWs), PEDOT:PSS, or carbon nanotubes (CNTs).

6. The method according to any one of claims 1 to 5, wherein the strip of transparent nanowires of the transparent antenna trace (A) has a thickness of 5-10 nm and is obtained by only one spray-coated layer.

7. The method according to any one of claims 4 to 6, wherein the strips of transparent nanowires in the heater busbar (3) have a thickness of 30-50 nm and are obtained by multiple spray-coated layers.

8. The method according to any one of claims 1 to 7, wherein the transparent antenna traces (A) comprise crossing traces (5) that cross the horizontal heating lines (4) and separating traces (6) that do not cross the heater (H).

9. The method according to any one of claims 1 to 8, wherein the transparent antenna trace (A) comprises a direct bond trace (8) connected to a busbar (3) or a horizontal heating line (4).

10. 10. The method according to any one of claims 1 to 9, wherein the transparent antenna trace (A) comprises a capacitive coupling trace (109) in a parallel position adjacent to a horizontal heating line (4) or a busbar (3), and the rear window (1) comprises at least one flat compliant structure (13) connected to the capacitive coupling trace (109), the flat compliant structure (13) being obtained by spray-coating a transparent strip made of a conductive material onto the inside of the glass plate (2).

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