Method for manufacturing a rear window of a vehicle provided with a heater-integrated 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 a heater-integrated 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 the same technology by rear window manufacturers who make heaters. 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-mentioned screen-printed plate.

[0003] To remove the frost and fog on the rear window provided with a heater, a battery voltage is applied between two electrodes (rheophores) of busbars disposed 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 layout of the heater to optimally distribute current across all horizontal lines of the heater and as uniformly as possible within each line, while at the same time striving to reduce the number of screen-printed heating lines necessary for fog removal in order to minimize costs.

[0006] The glass manufacturer provides elements used for the antenna with the same screen printing mask as those used for heater elements for glass defrosting.

[0007] The operating elements for the antenna comprise: - Horizontal lines of the heater and vertical or slightly inclined screen printing that intersects the horizontal lines of the heater either wholly or partially. The screen printing is used to optimize antenna performance by improving bandwidth or impedance matching. The maximum slope value is restricted and enforced by the glass manufacturer so as not to deviate the distribution of the heating current from the path and thereby impair the uniformity of the fog removal action. Such a restriction is a performance limitation with respect to the design of an antenna system integrated into the rear window of a vehicle. A greater line slope results in impedance matching over a wider band for the antenna, thereby resulting in a more uniform reception range at the frequencies of the target band. - Screen printing of the antenna power supply. This screen printing involves a copper monopole terminal with pads for interconnection provided by welding at one end and a connector for connection to an amplifier.

[0008] In terms of operation, the screen printing of the antenna power supply can be of various types: - Screen printing that couples with a heater. This operates as an electric field probe and acquires useful received signals captured by the heater in a conductive or radiative manner. Screen printing that directly couples with the heater is known, and it is physically connected to the heater on the side opposite to the pad. Similarly, screen printing that capacitively couples with the heater is known. The screen printing for capacitive coupling is not directly connected to the heater, and a screen printing section is provided at the opposite end with respect to the pad. The screen printing section faces the nearest heating line (generally at a distance of 3 to 15 mm) and extends in a parallel direction to obtain capacitive coupling. - A separate screen printing that operates by resonance without using coupling with a heater. Similarly, the separate screen printing has a pad and a copper wire having terminals for connecting to an amplifier. - Stub screen printing. This can be directly connected to the heater or disposed proximal to the heater. However, no pad for interconnecting with the amplifier is provided. Stub screen printing is used to optimize antenna performance by improving bandwidth or impedance matching.

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

[0010] Functional defrosting constraints The screen printing of an antenna directly connected to the heater can be realized only by a contact without delay corresponding to the heater, as in the case of direct coupling.

[0011] In the case of extended lines that intersect the line for removing frost, their slopes need to have limited values. They can be completely perpendicular to the vertical line or slightly inclined. The reason is that they must intersect the horizontal line only at equipotential points. Otherwise, the current is additionally divided corresponding to the intersection as the current flows along the intersection, and the strength of the current flowing along the horizontal line is reduced. This results in a lack of uniformity and reduces the effect of removing frost from the glass in the longitudinal direction. The free slope of the lines intersecting the heating line brings about more uniform performance in the target band.

[0012] Furthermore, the need to maintain a uniform current distribution for the removal of frost on the glass limits the possibility of realizing screen printing of antenna power supplies with direct coupling or capacitive coupling that can capture useful signals in areas other than the area 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 parts by tracing the screen printing of the antenna power supply that can be coupled proximal to the point where the electric field strength is higher. This reduces the effectiveness of the antenna integrated into the rear window and impairs the freedom in optimizing the layout for improving performance.

[0013] Constraints regarding ion migration This phenomenon occurs in response to the capacitance coupling between the screen printing of the antenna power supply and the screen printing of the heater when the potential difference becomes a significant value when power is supplied to the heater, or when the distance between the screen prints is too short. The actual effects of ion migration occur when moisture, condensation, or impurities (such as dust, metal dust, etc.) are present on the glass surface. The actual effect of ion migration is the generation of a current flowing from the horizontal line of the heater, thereby providing energy towards the screen printing of the antenna power supply with capacitance coupling at a potential difference from zero. The current density is very strong, causing overheating of the antenna trace due to the Joule effect, dissipating the antenna trace, and then causing damage to the screen-printed layout of the glass. To improve such defects, a minimum safety distance is currently imposed on the capacitance coupling. It varies from 8 to 18 mm depending on the specific case and the vehicle manufacturer, and is significantly higher than the processing limits of glass manufacturers who can produce screen prints at distances less than 5 mm, improving the effectiveness of the capacitance coupling and the strength of the captured signal.

[0014] Constraints on Functional Vision The layout of the heating screen print is evaluated with respect to the visual impact on the vehicle driver. Such a layout must be made so that the lines do not obstruct the rear vision of obstacles encountered during driving. Generally, vehicle manufacturers tend to leave the central part of the rear window empty and avoid providing lines in the center of the glass or around the central region of the glass.

[0015] Aesthetic Constraints Since it is visible from the outside, automobile manufacturers consider the rear window of a vehicle as an aesthetic part of the vehicle that must be approved by the design department. Specifically, the design of the rear window line must comply with aesthetic rules, and automobile manufacturers sometimes change the layout of the antenna trace even though the antenna system functions well with respect to signal reception. Usually, for aesthetic reasons, the design of the antenna is restricted with respect to the number of vertical lines and the shape of the antenna power supply trace. Specifically, the antenna power supply trace must adapt to the rear window following the shape of the heater. Currently, in order to reduce the aesthetic impact caused by the presence of the antenna trace, the antenna trace is hidden in the black band area, i.e., the peripheral area of the glass. The black body area is defined internally by the transparent part in the center of the glass and externally by the adhesion area between the rear window and the body of the vehicle door. The trace is deposited on the black band, and the black band has a covering property such that it cannot be seen from the outside. However, depending on the type of vehicle, this is not always possible because the rear window is not extended particularly vertically, so that the black band becomes very narrow. In such cases, the space available for the antenna trace is very small, it is impossible to combine the screen printing of the antenna power supply with the internal center line of the heater, the design becomes complicated and the performance is impaired.

[0016] U.S. Patent No. 5,952,977 discloses a solution for improving rear visibility through a rear window impaired by the use of vertical lines disposed in the central region of the glass. Such vertical lines provide good performance with respect to reception, but reduce rear visibility and are positioned exactly in the driver's visual trajectory. To solve this problem and to maintain a high level of performance, U.S. Patent No. 5,952,977 proposes a system with two vertical lines mounted on the sides of the central region of the rear window. These two vertical lines cross all the horizontal heating lines, are extended at the top of the heater, and form a "T" coupled by capacitive coupling using screen printing of the antenna power supply. Each vertical line is connected to a pad and a monopole wire, either towards the receiver or towards an amplifier disposed in an intermediate position. Some variations of the above capacitive coupling between the vertical lines of the heater and the screen printing of the antenna power supply have been proposed. However, even though the central region of the rear window is advantageously left empty and rear vision is improved, such a solution is impaired with a negative aesthetic effect due to the complexity of the power supply lines and the complexity of the capacitive coupling. This is particularly detrimental to automobile manufacturers and implies some limitations for the possible applications. Another drawback occurs when a rear window with a small area without a heater is applied between the peripheral edge of the rear window and the area for adhesion / overlap to a metal door / body. In this case, there is not enough space available for the above coupling.

[0017] European Patent No. 1502321 discloses an antenna trace layout in a heater composed of a set of vertical sections arranged in a step pattern perpendicular to a horizontal heating line. Each vertical section is in contact with a pair of horizontal heating lines. Advantageously, a more direct radiation pattern is obtained from these solutions by a special distribution of the signal current useful for radio reception. This radio reception is derived from an array of vertical sections without changing the distribution of the heating current for removing fog and frost on the rear window. This is because the vertical sections of the antenna connect a pair of horizontal lines between two equipotential points, whereby a direct current with a heating function flows along each horizontal line and does not flow through the vertical sections. Such a solution is impaired by providing a plurality of vertical sections distributed over the width and height of the entire heater, including the central region of the rear window. As a result, the influence of the above-mentioned vertical sections may be dangerous for the driver with respect to rear vision when compared with the presence of two conventionally simple and continuous vertical lines arranged in the central region of the rear window. Furthermore, the aesthetic impact of the step pattern of the heater, which is more irregular than before, is not understood by automobile manufacturers who tend to prefer clear, simple, and regular shapes and patterns.

[0018] U.S. Patent No. 9,231,213 discloses a system that provides for integrating 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 the interconnection of antennas or passive elements such as resistors, capacitors, and inductors. Further, graphene is used as an active channel for the realization of RF devices (such as switches, amplifiers, etc.). Additionally, a method called "local selectivity conductivity control method" is imposed. This provides for the controlled deposition of a nanomaterial layer in regions where higher conductivity unavoidably results in loss of transparency. The antenna is a separate element and is not integrated with the heater. The antenna layout is common and does not have any particular elements (such as a slot antenna with a coplanar structure and power supply). For the dielectric layer of the capacitor, the 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 of a vehicle that includes a mesh grid obtained by depositing transparent conductive nanowires (AgNW, ITO, CNT) on a glass plate. Such a grid can be part of an antenna or a heating element. The deposition of the grid of transparent nanowires 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. Further, the application of the adhesive layer is inaccurate and complex.

Prior Art Documents

Patent Documents

[0020]

Patent Document 1

Patent Document 2

Patent Document 3

[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 in 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 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, and thus avoid changing the distribution of the current required to remove the frost on the glass. It is desirable to separate it so as to block the region of the stronger electric field of the received signal. 3. The high-impedance vertical lines of direct current (DC) are used to prevent the current used to remove frost from deviating from the normal path along the horizontal heating line in order to enjoy a higher degree of freedom regarding the outer shape 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 inside the rear window. On top of that, conductive lines made of nanomaterials (copper, silver, and carbon-based nanomaterials) are deposited. They act as antennas and are invisible because they are more highly inherently transparent.

[0027] Several nanomaterials can be considered for the realization of transparent antenna traces. Examples include silver nanowires (AgNWs), copper nanowires (CuNWs), PEDOT:PSS, and carbon nanotubes (CNTs). These nanomaterials can be deposited by realizing a transparent conductive film using various techniques such as drop melting, Mayer rod coating, vacuum filtration, spin coating, and spray coating. Spray coating technology is preferably selected because it is adaptable, large-scale realizable, and inexpensive.

[0028] The deposition solution is obtained using a suitable process according to the materials 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 Dynol604 agent and 200 mg of ethylene glycol (EG) are added to improve conductivity. Next, this solution is sonicated for 30 seconds to disperse the lumps.

[0030] The CNT-based solution is composed of DI water, 90% semiconductor CNT, and sodium dodecyl sulfate (SDS) acting as a dispersant. 1 wt% of SDS is dissolved in DI water, and 0.03 wt% of CNT is added. This solution is processed by an ultrasonic processor at 50% power for 25 minutes, centrifuged at 15 krpm for 90 minutes, and used as CNT ink, so 80% of the supernatant is separated.

[0031] To realize copper nanowire ink, 300 mg of cuprous chloride 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 sonicated at 200 W for 60.

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

[0033] Referring to Figure 1, the spray coating technique realizes a film that is thin, reproducible, homogeneous, large-scale realizable, inexpensive, and provided at a low substrate temperature using a fully automated system. Such a system includes a spray nozzle (N) and a heated plate (P) on which a substrate (S) is positioned. This spray coating technique requires simultaneous control of several parameters such as spray pressure, flow rate, scanning speed, height (distance (D) between the nozzle and the substrate), and the temperature of the substrate (S). A specific form of the sprayed material can be realized by using a mask (plastic or metal) that covers the parts of the substrate where the material is not deposited and does not cover the parts where the functional layer is deposited.

[0034] Advantageously, a cleaning process using oxygen and plasma can be performed before spray coating the substrate (S) to make the surface of the substrate more hydrophilic and improve the wetting characteristics and film formation on the active substrate. The time of the cleaning process varies depending on the type of material. When the passive substrate is glass, the oxygen plasma cleaning process is performed for 1 minute.

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

[0036] Figure 3 shows the transmittance of the AgNW film according 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 magnification and high magnification. Figure 4(D) is the conversion of a binary image for determining the diameter of one wire in the copper nanowire layer. Figure 4E shows the transmittance spectrum of the CuNW film by increasing the wire density.

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

[0039] Considering its diversity, the spray coating technique can also be used to obtain an insulating layer. Insulating transparent polymers such as polymethyl methacrylate (PMMA) dissolved in solutions and metal oxides in sol-gel form (the most commonly used are sol-gels of aluminum oxide and titanium oxide) can be atomized and deposited by the above spray coating technique. The realization of thin layers made of these materials, characterized by transparency and low conductivity, isolates several metal layers and prevents any contact.

[0040] After the deposition of each material, heat treatment or optical treatment of the substrate (UV pulsed light or IR light) is carried out to cause evaporation of the solvent and dissolution of the dispersion 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-gel).

[0041] According to the above description, the realization of the rear window is obtained by sequentially depositing various functional materials using a suitable mask. Specifically, the process includes the following steps. 1. Step of preparing printing ink with transparent nanowires. 2. Step of preparing a transparent dielectric substrate (cleaning and, if any, plasma activation). 3. Step of positioning and aligning the screen printing mask. 4. Step of spray coating the printing ink. 5. Step of subjecting the substrate to heat or optical post-treatment.

[0042] These steps are repeated for all materials. In the case of the integration of the heating line and the conductive line dedicated to the antenna, all processes are repeated at least three times. Specifically, the process is as follows. a. Steps 1 to 5 for the deposition of the conductive heating line (thickness from 30 nm to 500 nm depending on the nanomaterials used and the transparency level). b. Steps 1 to 5 for the deposition of the electrical insulating material (thickness from 100 nm to 10 microns depending on the nanomaterials used and the transparency level). c. Steps 1 to 5 for the deposition of the conductive line for the antenna. The material used in this step does not necessarily have to be the same as the material used in step a (the selection of the material and thickness is determined by the desired impedance).

[0043] The foregoing 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 the conventional system. However, the rear window of the present invention overcomes the limitations of the rear window of the prior art. This is because the aesthetic impact of the antenna line is zero, and it provides higher diversity at the design stage. This is to enable electromagnetic coupling of the antenna trace in the more inner region of the heater, as well as the outer shape and solution that were not allowed in the so-called prior art.

[0044] New types of coupling and screen printing for the antenna area: - Direct coupling with a horizontal line other than the first line at the top or the last line at the bottom. - Capacitive coupling with a horizontal line other than the first line at the top or the last line at the bottom. - Capacitive coupling between the line of the heater and a closer horizontal line. The presence of the oxide deposition usually electrically insulates the proximal coupling that is normally subject to ion migration. - New overlapping capacitive coupling. Instead of being the same as the surface of the heater, it is usually placed only a few millimeters above the horizontal heating screen printing. The screen printing of the antenna power supply can be overlapped at the same height as the heating screen printing, and can be capacitively coupled in the transverse direction only by the presence of the oxide layer in the intermediate position, with almost zero gap, thus creating a capacitive coupling with a large strength. - Newly extended direct coupling. By using the deposition of nanowires with a controlled high impedance value, an extended direct coupling band is created instead of a coupling with no delay (a more restricted band). - High-impedance intersecting screen printing with a high tilt value with respect to the vertical direction and less interference with the current path imposed on the horizontal heating line. - Screen printing of antenna power supply with direct coupling or capacitive coupling. This includes a concentrated flat structure obtained by spray coating of transparent copper nanowires (or silver nanowires), and an insulating oxide layer for obtaining a capacitance or dielectric element according to specific requirements of an impedance adapter at a desired frequency. - Stud fit screen printing applicable to horizontal lines other than the top first line or the bottom last line. - Antenna system layout considering transparency introduced by nanowires used in traces, with multiple vertical lines at a more central position of the rear window, which is impossible with current ones. - Possibility of extending the transparency of screen printing to heating lines so as to significantly improve the driver's rear vision.

[0045] Further features of the present invention will become more apparent from the following detailed description, which is merely illustrative and non - limiting, with reference to the embodiments shown in the accompanying drawings.

Brief Description of the Drawings

[0046]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 4E

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 9A

Figure 10

Figure 10A

Figure 11

Figure 12

Figure 13

Figure 13A

Figure 13B

Figure 13C

Figure 14

DETAILED DESCRIPTION OF THE INVENTION

[0047] Referring to FIGS. 5 to 14, the rear window of the present invention is disclosed, where it is generally indicated by reference numeral (1).

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

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

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

[0051] The outside of the glass plate (2) is suitable for being directed towards the exterior of the vehicle, and the inside of the glass plate (2) is suitable for being directed towards the interior of the vehicle.

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

[0053] The heater (H) includes two busbars (3) made of a conductive material, which are arranged vertically near the side edges of the glass plate. Each of the busbars (3) is electrically connected to the anode and cathode of the vehicle battery so as to define a potential difference between the two busbars (3).

[0054] The busbars (3) can be made by a conventional method by screen printing a conductive paste of copper or silver on the glass plate (2).

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

[0056] The busbars (3) are connected by a plurality of horizontal heating lines (4). For example, 16 horizontal heating lines can be provided at equidistant parallel positions.

[0057] The horizontal heating lines (4) can be made by a conventional method by screen printing a conductive paste of copper or silver on the glass plate (2).

[0058] Advantageously, in order to obtain a transparent horizontal heating line, the horizontal heating line (4) can be obtained by spray coating transparent nanowires on 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 the deposition of a single layer of nanowires.

[0059] By applying a potential difference between two busbars (3), a current circulation is generated in the horizontal heating line (4), which is heated to remove the frost on the rear window.

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

[0061] In FIG. 5, the antenna trace (A) comprises an intersection trace (5) and a separation trace (6).

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

[0063] The separation trace (6) is disposed inside the glass plate (2) above the heater (H) and forms a pattern, for example, in an "S" shape (60) with a vertical trace (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 normally not 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 an impedance adapter, consisting of a chip crimped or adhered to the pad (7).

[0066] The crossing trace (5) and the separation trace (6) are obtained by spray coating of transparent nanowires. The crossing trace (5) crosses the horizontal heating line (4), and this fact should be taken into account that there is no problem with the spray coating of nanowires.

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

[0068] The separation trace (6) can be easily obtained by the nozzle (N) of FIG. 1.

[0069] FIG. 6 shows an example in which the antenna trace (A) includes a direct connection trace (8) disposed on the plate (2) above the heater, in addition to the crossing trace (5). The first direct connection trace (8) is connected to the pad (7) and the bus bar (3). The second direct connection trace (8) is connected to the pad (7) and a horizontal heating line (4) such as the highest horizontal heating line.

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

[0071] Also in such a case, the direct connection trace (8) is obtained by directly spray coating transparent nanowires on the plate (2). The width and thickness of the direct connection trace (8) are the same as those of the crossing trace (5) and the separation trace (6).

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

[0073] The intersecting direct-coupling trace (80) is realized using transparent nanowire technology. The transparent nanowire technology enables obtaining a wide direct-coupling bandwidth. This is because the transparent nanowires have a controlled impedance value so that the current flow that must flow only along the horizontal heating line (4) does not deviate.

[0074] FIG. 8 shows an example that also includes a capacitive coupling trace (9) where, in addition to the cross trace (5), the antenna trace (A) is disposed inside the plate (2) above the heater in a parallel position close to the highest horizontal heating line (4). The capacitive coupling (9) is connected to a pad (7) disposed in the upper region inside the plate and is suitable for electrically connecting to electronic components such as an amplifier or an impedance adapter.

[0075] Also in this case, the capacitive coupling trace (9) is obtained by directly spray-coating transparent nanowires on the plate (2), and its width and thickness are the same as those of the direct-coupling traces (8, 80) of the cross trace (5) and the separation trace (6).

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

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

[0078] The transparent oxide layer (10) is deposited on the horizontal heating line (4). As shown in FIG. 9A, a horizontal gap (d) 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 with respect to the horizontal heating line (4) having the transparent oxide layer (10) applied thereon so as to define a horizontal gap (d) between the axis of the horizontal heating line (4) and the axis of the capacitive coupling trace (9). 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 migration between the capacitive coupling trace (9) and the horizontal heating line (4).

[0081] FIG. 9 shows a capacitive coupling trace (109) disposed on the transparent oxide layer (10) in a parallel position close to the bus bar (3). In this case, the transparent oxide layer (10) is L-shaped. The capacitive coupling trace (109) near the bus bar is connected to the capacitive coupling trace (9) that provides coupling with the horizontal heating line (4).

[0082] FIGS. 10 and 10A show an example in which the capacitive coupling trace (9) is obtained by spray coating on the transparent oxide layer (10) and disposed in an aligned and overlapping position with respect to the horizontal heating line (4), that is, with a horizontal gap of zero in cross section. Considering the above, the vertical gap (s) is equal to the thickness of the transparent oxide layer (10) く and is defined between the horizontal heating line (4) and the capacitive coupling line (9). Advantageously, the thickness of the transparent oxide layer (10) is less than 5 mm.

[0083] Such a solution ensures an effective capacitance with no ion movement between the capacitive coupling trace (9) and the horizontal heating line (4).

[0084] Figure 11 shows an internal capacitive coupling trace (209) disposed 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) disposed on a plate (2) outside the heater by a connection trace (105) crossing the horizontal heating line (4).

[0085] The rear window (1) also has electrostatic internal traces (309) in a vertical position, which cross a plurality of horizontal heating lines and are coupled to the cross traces (5).

[0086] The rear window (1) also includes the following. - An external stub (400) disposed on the plate (2) outside the heater and connected to the horizontal heating line (4). - An internal stub (401) disposed on the plate (2) inside the heater between two horizontal heating lines (4) and connected to the horizontal heating line (4).

[0087] Figure 12 shows a rear window in which an antenna trace (A) includes diagonal crossing lines (50) that cross a plurality of horizontal heating lines at an angle of, for example, 30 to 50 degrees in a diagonal direction.

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

[0089] The diagonal crossing trace (50) is realized using high-impedance nanowires so that the current flow does not deviate from the horizontal heating line (4).

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

[0091] FIGS. 13A, 13B, and 13C show three examples of flat conforming structures. The flat conforming structure is a stub of a transformer or a concentrated inductance and is capacitive.

[0092] The flat conforming structure (13) is obtained by a spray coating of transparent nanowires.

[0093] FIG. 14 shows an example of a rear window in which a horizontal heating line (4) of a heater is obtained by spray coating transparent nanowires, and for this reason, the horizontal heating line (4) is shown by a dashed line.

[0094] FIGS. 5 to 14 show various examples of heaters in which the antenna trace (A) has different types and layouts, and these types and layouts of the antenna trace can be combined with each other.

Claims

1. A method for manufacturing a rear window (1) of a vehicle, comprising: preparing a glass plate (2) having an outer side suitable for installation facing the outside of the vehicle and an inner side suitable for installation facing the inside of the vehicle; forming a heater (H) on the inner side of the glass plate (2), the heater (H) having two bus bars (3) electrically connected to the anode and cathode of the vehicle battery respectively and a plurality 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 surface of the inner side of the glass plate (2) where the heater (H) is formed, wherein the step of forming the transparent antenna trace (A) includes: preparing a transparent oxide; hydrophilically treating the surface of the inner side of the glass plate (2) where the heater (H) is formed by cleaning with oxygen and plasma; positioning and forming a printing mask on the hydrophilically treated surface; spray coating the transparent oxide on the surface where the printing mask is formed to form a transparent oxide layer (10); preparing a printing ink containing transparent nanowires; positioning and forming a printing mask on the surface where the transparent oxide layer (10) is formed; spray coating the printing ink on the surface where the printing mask is formed to form a capacitance coupling trace (9) as a transparent antenna trace (A); performing a thermal or optical post-treatment on the surface including the transparent oxide layer (10) and the transparent antenna trace (A), wherein a part of the transparent antenna trace (A) is close to and parallel to the horizontal heating line (4) on the opposite side across the transparent oxide layer (10) as a capacitance coupling trace (9).

2. The capacitance trace (9) overlaps the horizontal heating line (4) with the transparent oxide layer (10) applied thereon, such that a vertical gap (s) having the same thickness as the transparent oxide layer (10) is formed between the horizontal heating line (4) and the capacitance coupling trace (9).

3. The method according to claim 1, wherein the transparent oxide layer (10) has a thickness of less than 5 mm.

3. The capacitive coupling trace (9) is staggered with respect to the horizontal heating line (4) to which the transparent oxide layer (10) is applied above so as to secure a horizontal gap (d) between the axis of the horizontal heating line (4) and the axis of the capacitive coupling trace (9), the horizontal gap (d) is less than 5 mm, and the thickness of the transparent oxide layer (10) is less than 5 mm. The method according to claim 1.

4. The bus bar (3) and the horizontal heating line (4) of the heater are obtained by spray coating a strip of transparent nanowires made of a conductive material on the side of the glass plate (2). The method according to any one of claims 1 to 3.

5. The transparent nanowires include silver nanowires (AgNW), copper nanowires (CuNW), PEDOT:PSS, or carbon nanotubes (CNT). The method according to any one of claims 1 to 4.

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

7. The strip of transparent nanowires in the bus bar (3) of the heater has a thickness of 30 to 50 nm and is obtained by a plurality of spray-coated layers. The method according to any one of claims 4 to 6.

8. The transparent antenna trace (A) includes an intersection trace (5) that intersects the horizontal heating line (4) and a separation trace (6) that does not intersect the heater (H). The method according to any one of claims 1 to 7.

9. The transparent antenna trace (A) includes a direct coupling trace (8) connected to the bus bar (3) or the horizontal heating line (4). The method according to any one of claims 1 to 8.

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

Images