Vehicle antenna device

Abstract

A vehicle antenna device of the present invention comprises a dielectric substrate having a first main surface and a second main surface, and an electrically conductive film provided on the second main surface side and having an area of more than or equal to 0.025 m2 in a plan view of the dielectric substrate. The electrically conductive film has a sheet resistance value of less than or equal to 1.5×103Ω / sq. AM broadcast waves can be received from a feed point electrically connected to the electrically conductive film.

Description

[Technical Field]

[0001] This invention relates to a vehicle antenna device. This application claims priority based on Japanese Patent Application No. 2021-184698, filed in Japan on November 12, 2021, and the contents of that application are incorporated herein by reference. [Background technology]

[0002] In recent years, vehicle openings, particularly vehicle windows, have been coated with (transparent) conductive films such as Low-E and heat-reflective coatings, or equipped with dimmable films that can electrically (actively) change the visible light transmittance, thus providing thermal / optical added value. On the other hand, when a conductive film is coated onto a dielectric material such as glass, the desired antenna gain cannot be obtained as a glass antenna, such as conventional vehicle window glass, where a linear conductive pattern is arranged on the vehicle window glass to receive a predetermined broadcast wave. As an example of using a conductive film coating as an antenna, Patent Document 1 is known.

[0003] Patent Document 1 describes an antenna element comprising a conductive film that is heated by applying a voltage between a pair of busbars, and which functions as an antenna capable of receiving terrestrial digital television broadcast waves, DAB (Digital Audio Broadcast) broadcast waves, and FM broadcast waves. Furthermore, Patent Document 1 states that by providing a grid area in which the area around the conductive portion of the conductive film is removed to increase resistance, it can also function as an antenna capable of receiving AM broadcast waves. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-140669 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, when realizing an antenna for receiving AM broadcast waves using such a conductive film, there was a problem in that the number of steps required to process the conductive film, such as creating a grid, increased, and the process became more complex.

[0006] The present invention provides a vehicle antenna device that can easily receive AM broadcast waves using a conductive film in a vehicle window glass. [Means for solving the problem]

[0007] A vehicle antenna device according to one aspect of the present invention comprises a dielectric substrate having a first main surface and a second main surface, and a device provided on the second main surface side, the area of ​​the dielectric substrate in plan view being 0.025 m² 2 The device comprises a conductive film having the above characteristics. The conductive film has a diameter of 1.5 × 10 3 The sheet has a resistance value of Ω / □ or less, and AM broadcast waves can be received from a power supply point electrically connected to the conductive film.

[0008] In a vehicle antenna device according to one aspect of the present invention, the power supply point may be located in the center of the conductive film, at a distance of 150 mm or more from the edge of the dielectric substrate in a plan view of the dielectric substrate.

[0009] In a vehicle antenna device according to one aspect of the present invention, the outer edge of the conductive film may be substantially rectangular in a plan view of the dielectric substrate.

[0010] In a vehicle antenna device according to one aspect of the present invention, the feed point electrically connected to the conductive film is a first feed point, and the device includes an antenna provided on the first main surface side that receives radio waves of at least one of the frequencies of the VHF band and the UHF band, an antenna electrode positioned inward from the outer edge of the void region within the conductive film in a plan view of the dielectric substrate, an antenna conductor connected to the antenna and positioned on the first main surface side, and a filter between the conductive film and a ground conductor that allows signals of at least one of the frequencies of the VHF band and the UHF band to pass through and blocks signals of the AM broadcast wave frequency band. The antenna conductor may be electrically connected to the antenna electrode and capable of receiving at least one of the frequencies of the VHF band and the UHF band based on signals received with the antenna electrode as a second feed point.

[0011] In a vehicle antenna device according to one aspect of the present invention, the antenna conductor and the antenna electrode may be electrically connected by capacitive coupling.

[0012] In a vehicle antenna device according to one aspect of the present invention, the antenna conductor and the antenna electrode may be directly connected by a connecting conductor disposed in a through-hole of the dielectric substrate.

[0013] In a vehicle antenna device according to one aspect of the present invention, the dielectric substrate is a first dielectric substrate, and comprises a second dielectric substrate arranged parallel to the second main surface on the second main surface side of the first dielectric substrate, and an interlayer film arranged between the first dielectric substrate and the second dielectric substrate. The second dielectric substrate has a third main surface on the side of the first dielectric substrate and a fourth main surface on the opposite side of the third main surface, the conductive film is arranged between the first dielectric substrate and the second dielectric substrate, and the antenna electrode may be arranged on the side of the fourth main surface.

[0014] In a vehicle antenna device according to one aspect of the present invention, the conductive film may be arranged in contact with the second main surface.

[0015] In the vehicle antenna device according to one aspect of the present invention, the intermediate film includes a first intermediate film and a second intermediate film, and the conductive film may be sandwiched between the first intermediate film and the second intermediate film.

[0016] In the vehicle antenna device according to one aspect of the present invention, the conductive film may be a dimming film containing a conductor.

[0017] In the vehicle antenna device according to one aspect of the present invention, the conductive film may be disposed in contact with the third main surface or the fourth main surface.

[0018] In the vehicle antenna device according to one aspect of the present invention, the intermediate film includes a first intermediate film and a second intermediate film, the conductive film includes a first conductive film and a second conductive film, and the first conductive film and the second conductive film are disposed at two positions among the positions on the second main surface, the positions between the first intermediate film and the second intermediate film, the positions on the third main surface, and the positions on the fourth main surface, and are arranged in order from the one closer to the first dielectric substrate. The second conductive film may have a second hole region arranged to overlap with a first hole region which is the hole region of the first conductive film in a plan view of the first dielectric substrate.

[0019] In the vehicle antenna device according to one aspect of the present invention, the first conductive film may be disposed in contact with the second main surface, and the second conductive film may be sandwiched between the first intermediate film and the second intermediate film.

[0020] In the vehicle antenna device according to one aspect of the present invention, the first conductive film may be a conductor for heat ray reflection, and the second conductive film may be a dimming film containing a conductor.

[0021] In the vehicle antenna device according to one aspect of the present invention, the conductive film includes a third conductive film disposed in contact with the fourth main surface, and the third conductive film may be a conductor for a low-emissivity film.

[0022] In a vehicle antenna device according to one aspect of the present invention, the first conductive film may be sandwiched between the first interlayer and the second interlayer, and the second conductive film may be arranged in contact with the fourth main surface.

[0023] In a vehicle antenna device according to one aspect of the present invention, the first conductive film is a light-adjusting film containing a conductor, and the second conductive film may be a conductor for a low-emission film.

[0024] In a vehicle antenna device according to one aspect of the present invention, the antenna is capable of receiving FM broadcast wave frequencies and includes an AM amplifier and an FM amplifier, wherein a signal in the frequency band of AM broadcast waves is input to the AM amplifier from the first feed point, and a signal in the frequency band of FM broadcast waves is input to the FM amplifier from the second feed point.

[0025] In a vehicle antenna device according to one aspect of the present invention, the filter is a capacitor, and the capacitance of the capacitor may be 5pF to 150pF.

[0026] In a vehicle antenna device according to one aspect of the present invention, the antenna may be arranged surrounded by a cover member that protrudes outward from the first main surface side of the dielectric substrate.

[0027] In a vehicle antenna device according to one aspect of the present invention, the dielectric substrate may be a glass substrate.

[0028] In a vehicle antenna device according to one aspect of the present invention, the dielectric substrate may be mounted on the roof of the vehicle parallel to the horizontal plane of the vehicle. [Effects of the Invention]

[0029] According to an aspect of the present invention, a vehicle antenna device is made of a vehicle window glass using a conductive film, and can easily receive AM broadcast waves using the conductive film. [Brief explanation of the drawing]

[0030] [Figure 1] This is a schematic perspective view showing an example of a vehicle antenna device according to the first embodiment. [Figure 2] This is a cross-sectional view showing an example of a vehicle antenna device according to the first embodiment. [Figure 3A] This is a plan view diagram showing an example of a vehicle glass according to the first embodiment. [Figure 3B] This is a plan view diagram showing an example of a vehicle glass according to the first embodiment. [Figure 3C] This is a plan view diagram showing an example of a vehicle glass according to the first embodiment. [Figure 4] This figure shows the equivalent circuit of the vehicle antenna device according to the first embodiment. [Figure 5] This figure shows the antenna characteristics of the vehicle antenna device of the first embodiment for AM broadcast waves. [Figure 6] This figure shows the antenna characteristics of the FM broadcast wave of the vehicle antenna device according to the first embodiment. [Figure 7] This figure shows the relationship between the ground capacitance and sheet resistance of the vehicle antenna device according to the first embodiment. [Figure 8] This figure shows the relationship between the ground capacitance and antenna capacitance of the vehicle antenna device according to the first embodiment. [Figure 9] This figure shows an example of antenna characteristics when a high-resistance conductive film is used in the vehicle antenna device of the first embodiment. [Figure 10] This is a cross-sectional view showing an example of a vehicle antenna device according to a second embodiment. [Figure 11] This is a cross-sectional view showing an example of a vehicle antenna device according to a third embodiment. [Figure 12] This is a cross-sectional view showing an example of a vehicle antenna device according to the fourth embodiment. [Figure 13] This is a cross-sectional view showing an example of a vehicle antenna device according to the fifth embodiment. [Figure 14] This is a cross-sectional view showing an example of a vehicle antenna device according to the sixth embodiment. [Figure 15]This is a cross-sectional view showing an example of a vehicle antenna device according to the seventh embodiment. [Figure 16] This is a cross-sectional view showing an example of a vehicle antenna device according to the eighth embodiment. [Modes for carrying out the invention]

[0031] Hereinafter, an embodiment of the vehicle antenna device of the present invention will be described with reference to the drawings. In the description of the embodiments, the terms "first main surface side," "second main surface side," "third main surface side," and "fourth main surface side" are used. Each of these terms has a meaning that includes a position on the surface of the main surface, or a position in the space facing the main surface that is away from the main surface. For example, in the relative positional relationship between an arbitrarily selected member A and the main surface, "member A is positioned on the main surface side" means not only that member A and the main surface are in direct contact, but also that member A is positioned so as to be separated from the main surface. Furthermore, when the main surface and member A are separated, there may or may not be an intervening object between the main surface and member A.

[0032] [First Embodiment] Figure 1 is a schematic perspective view showing an example of a vehicle antenna device 1 according to the first embodiment. Figure 2 is a cross-sectional view showing an example of a vehicle antenna device 1 according to this embodiment. Note that the cross-sectional view shown in Figure 2 is a cross-sectional view taken along line AB of area AR1 in Figure 1.

[0033] As shown in Figures 1 and 2, the vehicle antenna device 1 uses vehicle glass 10. The vehicle antenna device 1 comprises the vehicle glass 10, an antenna section 20, an amplifier section 30, and a filter 40. The filter 40 may be a high-pass filter or a band-stop filter. Unless otherwise specified, the following description will refer to it as a high-pass filter 40.

[0034] The vehicle glass 10 is, for example, a roof glass installed on the roof of a vehicle. The vehicle glass 10 is mounted on the roof of the vehicle parallel (including approximately parallel) to the horizontal plane of the vehicle. Now, with reference to Figure 2, an example of the configuration of the vehicle glass 10 will be described.

[0035] As shown in Figure 2, the vehicle glass 10 is, for example, a single pane of glass. The vehicle glass 10 comprises a glass substrate 11, an antenna conductor 12, a conductive film 13, an antenna electrode 15, a feed point 16, and a shielding layer 17.

[0036] The shape of the vehicle glass 10 may be curved or flat (non-curved). Furthermore, the vehicle glass 10 may have a single-curve shape, curved in either a vertical or horizontal direction (relative to one side of the frame) when mounted on a vehicle. The vehicle glass 10 may also have a double-curve shape, curved in both the vertical and horizontal directions. The single-curve shape may be curved in only one direction. The double-curve shape may be curved in two or more different directions. When the vehicle glass 10 has a curved shape, the minimum value of the radius of curvature of the vehicle glass 10 is preferably 500 mm or more and 100,000 mm or less.

[0037] The glass substrate 11 is an example of a dielectric substrate and has a first main surface F1 and a second main surface F2. In this embodiment, the main surface of the glass substrate 11 facing the outside of the vehicle is the first main surface F1. The main surface opposite to the first main surface F1 is the second main surface F2.

[0038] The antenna conductor 12 is an electrode connected to the antenna 21 and is positioned on the first main surface F1 side. The antenna conductor 12 is formed, for example, on the first main surface F1 side of the glass substrate 11, in contact with the glass substrate 11 (on the glass substrate 11). Here, an example of the configuration of the antenna conductor 12 will be explained with reference to Figures 3A to 3C, which are plan views of the antenna conductor 12 as seen from outside the vehicle.

[0039] Figures 3A to 3C are plan view diagrams showing an example of the vehicle glass 10 of this embodiment. Here, Figure 3A is a plan view of the vehicle glass 10 as seen from the outside of the vehicle (first main surface F1). As shown in Figure 3A, the antenna conductor 12 is arranged as a square electrode in the central part of the first main surface F1 of the glass substrate 11. That is, the antenna conductor 12 is formed in a rectangular shape (including a substantially rectangular shape) in a plan view of the glass substrate 11.

[0040] Returning to the explanation of Figure 2, the conductive film 13 can be, for example, a conductive film for heat reflection (heat-reflective film) or a conductive film for low emission (Low-E (Low Emissivity) coating) used to coat vehicle glass 10. A typical heat-reflective film is a metal film, and a typical metal film is silver (Ag). Low-emission films such as Low-E films ensure heat insulation by suppressing heat transfer by radiation. A Low-E film may be, for example, a laminated film containing a transparent dielectric film, an infrared reflective film, and a transparent dielectric film in that order. Typical transparent dielectric films are metal oxides and metal nitrides, and typical metal oxides are zinc oxide and tin oxide.

[0041] The conductive film 13 is provided on the second main surface F2 side of the glass substrate 11. In order for the conductive film 13 to function as an AM antenna for receiving AM broadcast waves, the area of ​​the glass substrate 11 in plan view is 0.025 m². 2 The above is preferable, and 0.050m 2 The above is more preferable, 0.100m 2 The above is even more preferable, 0.250m 2 The above is even more preferable, 0.500m 2 This is particularly preferable. The outer edge of the conductive film 13 is, for example, approximately rectangular in a plan view of the glass substrate 11, so as to match the shape of the glass substrate 11.

[0042] The conductive film 13 functions as an AM antenna and also as the antenna ground for antenna 21. Furthermore, the conductive film 13 is 1.5 × 10 3It is preferable to have a sheet resistance value of Ω / □ (ohm / square) or less. The sheet resistance value of the conductive film 13 is 1.0×10 3 Ω / □ or less is more preferable, 500 Ω / □ or less is further more preferable, 300 Ω / □ or less is particularly preferable, and 200 Ω / □ or less is most preferable. Also, the conductive film 13 has a void region VA inside in a plan view of the glass substrate 11.

[0043] The void region VA is arranged so as not to overlap with the antenna conductor 12 and the antenna electrode 15 in the thickness direction of the vehicle glass 10. Also, as shown in FIG. 3B, the void region VA is arranged as a square void region in a plan view of the glass substrate 11. That is, the void region VA is formed in a rectangular shape (including a substantially rectangular shape) in a plan view of the glass substrate 11.

[0044] Returning to the description of FIG. 2 again, the antenna electrode 15 is arranged on the second main surface F2 side inside the outer edge of the void region VA in a plan view of the glass substrate 11 and is electrically connected to the antenna conductor 12. The antenna electrode 15 is arranged, for example, in contact with the second main surface F2 of the glass substrate 11. The antenna electrode 15 and the antenna conductor 12 sandwich the glass substrate 11. With respect to the glass substrate 11, the antenna electrode 15 is formed on the opposite side to the antenna conductor 12. In the present embodiment, the antenna conductor 12 and the antenna electrode 15 are arranged so as to be capacitively coupled.

[0045] The distance between the antenna conductor 12 and the antenna electrode 15 is approximately 5 mm. For VHF and UHF frequency signals to be capacitively coupled, the distance of the dielectric between the conductors should be less than 30 mm, preferably 20 mm or less, and more preferably 10 mm or less. As described above, the thickness of the vehicle glass 10, including laminated glass as described later, is typically about 2 mm to 5 mm, so the distance between the antenna conductor 12 and the antenna electrode 15 is sufficient for capacitive coupling. Thus, if the thickness of the vehicle glass 10 is less than 30 mm, capacitive coupling between the antenna conductor 12 and the antenna electrode 15 becomes possible, and the circuit can be configured to amplify the signal received by the antenna 21 in the amplifier section 30.

[0046] In Figures 2 and 3A to 3C, the shielding layer 17 is positioned on the side of the conductive film 13 opposite to the glass substrate 11. The shielding layer 17 has a void region whose outer edge is positioned outside the outer edge of the void region VA of the conductive film 13. The shielding layer 17 is positioned on the conductive film 13 so that the power supply point 16 is exposed. The shielding layer 17 blocks visible light. The shielding layer 17 is an opaque colored ceramic layer. The color of the shielding layer 17 can be arbitrarily selected. Preferred colors for the shielding layer 17 are dark colors such as black, brown, gray, dark blue, or white, with black being more preferred. The void region of the shielding layer 17 is formed in a rectangular shape (including a substantially rectangular shape) in a plan view of the glass substrate 11, similar to the void region VA.

[0047] The arrangement of the shielding layer 17 can be arbitrarily selected. Furthermore, the shielding layer 17 may not be provided at all. In addition, if the shielding layer 17 is provided, it may be formed without any void regions, i.e., in a so-called "solid" state. In that case, the shielding layer 17 may be formed (in a solid) state on the second main surface F2 of the glass substrate 11. This is because, since the thickness of the shielding layer 17 is approximately 5 μm to 25 μm, even if a structure with the shielding layer 17 is adopted, the change in coupling capacitance between the antenna conductor 12 and the antenna electrode 15 is small, and capacitive coupling between the antenna conductor 12 and the antenna electrode 15 is possible regardless of the presence or absence of the shielding layer 17. In the following explanation, unless otherwise specified, the vehicle antenna device 1 will be described as having a shielding layer 17 with void regions.

[0048] The feed point 16 is an exposed portion of the conductive film 13. The feed point 16 is electrically connected to the conductive film 13. The vehicle antenna device 1 can receive AM broadcast waves from the feed point 16. In a plan view of the glass substrate 11, the feed point 16 is located in the center of the conductive film 13, at least 150 mm inward from the edge of the glass substrate 11. Even if the shielding layer 17 is formed as a solid without any void areas, the feed point 16 only needs to be electrically connected by capacitive coupling. Preferably, the feed point 16 is at least 200 mm inward from the edge of the glass substrate 11, and more preferably at least 300 mm inward from the edge of the glass substrate 11.

[0049] Figure 3C is a plan view of the vehicle glass 10 as seen from the inside of the vehicle (second main surface F2 side). As shown in Figure 3C, the antenna electrode 15 is formed in a rectangular shape (including a substantially rectangular shape) in a plan view of the glass substrate 11. Here, the antenna electrode 15 is positioned on the second main surface F2 side and is formed in a square shape.

[0050] Furthermore, the power supply point 16 is formed in a square loop shape in a plan view of the glass substrate 11. That is, the outer and inner edges of the power supply point 16 are each square in shape. Note that the loop shape may be a closed loop that is connected all the way around, or it may be a shape with one or more notches. If the power supply point 16 has notches, when the length of one full loop in a closed loop is standardized to "100", the length of the notched portion may be, for example, 40 or less, 30 or less, or 20 or less. Also, the length of the notched portion based on the above standardization may be, for example, 1 or more, 2 or more, or 5 or more. The feed point 16 is an example of a first feed point for receiving AM broadcast waves, and the antenna electrode 15 is an example of a second feed point for receiving FM broadcast waves.

[0051] Returning to the explanation of Figure 2, the antenna section 20 comprises an antenna 21 and an antenna cover 22. Antenna 21 is, for example, an antenna for receiving FM broadcast waves in the frequency band, an antenna for receiving DAB (Digital Audio Broadcast) broadcast waves in the frequency band, an antenna for receiving terrestrial digital television broadcast waves in the frequency band, an antenna for receiving GNSS (Global Navigation Satellite System) in the 1.2GHz and 1.6GHz bands, an antenna for receiving SDARS (Satellite Digital Audio Radio Service) in the 2.3GHz band, etc.

[0052] Here, the frequency band for FM broadcast waves (hereinafter referred to as the "FM band") is 76 MHz to 108 MHz, and the frequency band for DAB Band III broadcast waves (hereinafter referred to as the "DAB band") is 174 MHz to 240 MHz. In addition, the frequency band for terrestrial digital television broadcast waves (hereinafter referred to as the "DTV band") is 470 MHz to 710 MHz. Antenna 21 may be capable of receiving multiple frequency bands from among the FM broadcast wave frequency band, the DAB broadcast wave frequency band, the terrestrial digital television broadcast wave frequency band, the GNSS frequency band, and the SDARS frequency band.

[0053] The antenna 21 is positioned on the outside of the vehicle's glass 10 and connected to the antenna conductor 12. The antenna cover 22 (cover member) is a protruding cover that rests on the roof of the vehicle. The antenna cover 22 houses the antenna 21 inside. The antenna cover 22 is, for example, a shark fin antenna cover.

[0054] The amplifier section 30 amplifies the received AM broadcast signal received by the conductive film 13 as an AM antenna and the received FM broadcast signal received by the antenna 21, and outputs them to a receiver, for example. The input terminal for AM broadcast waves of the amplifier section 30 is connected to the feed point 16, and the input terminal for FM broadcast waves is connected to the antenna electrode 15. The output of the amplifier section 30 is supplied to the receiver via a transmission line such as a coaxial cable CB. Details of the amplifier section 30 will be described later.

[0055] The high-pass filter 40 is positioned between the conductive film 13 and the vehicle body (ground conductor), which is the ground. The high-pass filter 40 allows signals in at least one of the frequency bands of radio waves in the VHF band and UHF band to pass through between the conductive film 13 and the vehicle body, while blocking signals in the AM broadcast wave frequency band. In other words, the high-pass filter 40 grounds the conductive film 13 to the vehicle body in the VHF band and above, and electrically floats the conductive film 13 (high impedance state) in the AM band.

[0056] The high-pass filter 40 is, for example, a capacitor C1. The capacitance of capacitor C1 is preferably 5pF to 150pF, and more preferably 5pF to 100pF. Capacitor C1 is a capacitor element connected between the conductive film 13 and the vehicle body. Capacitor C1 may also be located within the amplifier section 30.

[0057] Next, with reference to Figure 4, the equivalent circuit of the vehicle antenna device 1 of this embodiment shown in Figure 2 will be described. Figure 4 shows the equivalent circuit of the vehicle antenna device 1 of this embodiment.

[0058] As shown in Figure 4, the amplifier section 30 includes an AM amplifier 31, an FM amplifier 32, and a signal mixer 33. In the vehicle antenna device 1 of this embodiment, the conductive film 13 functions as both an AM antenna and the antenna ground for the antenna 21. The conductive film 13 is connected to the ground of the amplifier section 30 and the signal ground of the output signal via a capacitor C1 in at least one of the VHF band and the UHF band. The ground of the amplifier section 30 and the signal ground of the output signal are connected to the vehicle body BD. The capacitance between the vehicle body BD and the conductive film 13 is defined as the antenna capacitance (C3).

[0059] The conductive film 13 is connected to the input signal line of the AM amplifier 31 via the feed point 16. The received signal received by the conductive film 13 as an AM antenna is input to the AM amplifier 31 as an input signal. Furthermore, in the AM broadcast frequency band, the conductive film 13 is electrically isolated from the ground of the amplifier section 30 and the signal ground of the output signal by the capacitor C1.

[0060] Furthermore, the antenna 21 is connected to the input signal line of the FM amplifier 32 via capacitor C2. Capacitor C2 is a capacitance formed by the antenna conductor 12 to which the antenna 21 is connected, and the antenna electrode 15. Capacitor C2 electrically connects the antenna conductor 12 and the antenna electrode 15 through capacitive coupling. The received signal from antenna 21 is then input to FM amplifier 32 as an input signal through capacitive coupling with capacitor C2.

[0061] The AM amplifier 31 amplifies the received signal of the AM broadcast wave received by the conductive film 13 and outputs it to the signal mixer 33. The FM amplifier 32 amplifies the received signal from the antenna 21 at a frequency of VHF or higher (for example, an FM broadcast wave) and outputs it to the signal mixer 33. A signal at a frequency of VHF or higher refers to, for example, one or more signals at at least one of the frequencies in the VHF band and the UHF band.

[0062] The signal mixer 33 mixes the received signal of the AM broadcast wave output by the AM amplifier 31 with the received signal of the VHF band or higher frequency (for example, the FM broadcast wave) output by the FM amplifier 32, and outputs the resulting received signal to a receiving device (not shown) via coaxial cable CB.

[0063] Next, the antenna characteristics of the vehicle antenna device 1 of this embodiment will be described with reference to Figures 5 to 9. Figure 5 shows the AM broadcast wave antenna characteristics of the vehicle antenna device 1 of this embodiment.

[0064] In Figure 5, the graph shows the measured antenna characteristics in the AM broadcast frequency band when the conductive film 13 is a conductor measuring 950 mm × 1150 mm. The solid line W1 represents the antenna sensitivity with an amplifier (AM amplifier 31), and the solid line W2 represents the antenna sensitivity without an amplifier. Note that when an amplifier (AM amplifier 31) is used, a capacitor C1 with a capacitance of 51 pF is connected.

[0065] In Figure 5, the conductive film 13 functions as an AM antenna for receiving AM broadcast signals. As shown by the solid line W1 in Figure 5, the vehicle antenna device 1 can achieve a sufficient antenna sensitivity of about 60 dB in the AM broadcast frequency band.

[0066] Figure 6 shows the antenna characteristics of the vehicle antenna device 1 of this embodiment for FM broadcast waves. Figure 6 shows the measured antenna characteristics in the FM broadcast frequency band when the conductive film 13 is a conductor measuring 950 mm × 1150 mm (solid line W3). The conductive film 13 functions as an antenna ground and is connected to a capacitor C1 with a ground capacitance of 51 pF. As shown by the solid line W3 in Figure 6, the vehicle antenna device 1 can achieve sufficient antenna sensitivity of 50 dB or more in the FM broadcast frequency band.

[0067] Next, with reference to Figure 7, the antenna characteristics of the vehicle antenna device 1 of this embodiment with respect to ground capacitance and sheet resistance will be described. Figure 7 shows the relationship between the ground capacitance and sheet resistance of the vehicle antenna device 1 of this embodiment. Figure 7 shows the simulated values ​​when the size of the conductive film 13 is 950 mm × 1150 mm, the antenna capacitance (C3) is 170 pF, the input capacitance of the AM amplifier 31 is 50 pF, and the frequency is 1000 kHz.

[0068] In Figure 7, the horizontal axis of the graph represents the capacitance (ground capacitance) of capacitor C1. The vertical axis of the graph represents the sheet resistance value of the conductive film 13. The dashed line W4 represents the sheet resistance value for the capacitance of capacitor C1 at which the sheet resistance of the conductive film 13 is -3dB lower than the signal attenuation of 0Ω / □. In other words, the dashed line W4 represents the maximum value of the sheet resistance that is within -3dB.

[0069] Furthermore, in Figure 7, range R1 indicates the range of sheet resistance where the aforementioned attenuation is within -3dB. Also, range RC1 indicates the range of capacitance (ground capacitance) of capacitor C1 from 5pF to 150pF. As shown in Figure 7, by setting the sheet resistance value to 1500Ω / □ or less within the capacitance range RC1 of capacitor C1, sufficient signal sensitivity for AM broadcast waves can be ensured.

[0070] Next, with reference to Figure 8, the antenna characteristics of the vehicle antenna device 1 of this embodiment with respect to ground capacitance and antenna capacitance (C3) will be described. Figure 8 shows the relationship between the ground capacitance and antenna capacitance of the vehicle antenna device 1 of this embodiment. Figure 8 shows the simulated values ​​when the size of the conductive film 13 is 950 mm × 1150 mm, the sheet resistance is 150 Ω / □, the input capacitance of the AM amplifier 31 is 50 pF, and the frequency is 1000 kHz.

[0071] In Figure 8, the horizontal axis of the graph represents the capacitance of capacitor C1 (ground capacitance), and the vertical axis represents the antenna capacitance (C3). The dashed line W5 represents the antenna capacitance (C3) relative to the capacitance of capacitor C1 at which the received signal attenuation is -10dB. In other words, the dashed line W5 represents the Min value (minimum value) at which the received signal attenuation is -10dB or greater.

[0072] Furthermore, in Figure 8, range R2 indicates the range of antenna capacitance (C3) where the aforementioned attenuation is -10dB or more. Also, range RC1 indicates the range of capacitance (ground capacitance) of capacitor C1 from 5pF to 150pF. As shown in Figure 8, within the capacitance range RC1 of capacitor C1, setting the antenna capacitance (C3) to 100pF or more ensures sufficient signal sensitivity for AM broadcast waves.

[0073] Next, with reference to Figure 9, the antenna characteristics when the conductive film 13 has high resistance will be described. Figure 9 is a diagram showing an example of the antenna characteristics when a conductive film 13 with relatively high resistance is used in the vehicle antenna device 1 of this embodiment. In Figure 9, the horizontal axis of the graph represents the receiving frequency, and the vertical axis represents the receiving voltage (dB). The solid line W6 shows the antenna sensitivity when the conductive film 13 is a copper tape with a size of 50 mm × 500 mm, and the dashed line W7 shows the antenna sensitivity when the conductive film 13 is a conductive film with a size of 50 mm × 500 mm and a sheet resistance of 150 Ω / □. Both the solid line W6 and the dashed line W7 are measured values.

[0074] As shown in Figure 9, there is no significant difference in reception sensitivity between a low-resistance (e.g., 0.1Ω / □ or less) copper tape (solid line W6) and a high-resistance conductive film (dashed line W7), and a reception sensitivity of 60dB or more can be secured in the AM broadcast frequency band. In other words, a relatively high-resistance conductive film 13 with a sheet resistance of about 150Ω / □, such as a Low-E coating (a conductive film for low radiation), can be used as an AM antenna. In this case, the Low-E coating may be applied not only to the vehicle window glass mounted on the roof, but also to the side windows and rear windows.

[0075] As described above, the vehicle antenna device 1 of this embodiment comprises a glass substrate 11 (dielectric substrate) and a conductive film 13. The glass substrate 11 has a first main surface F1 and a second main surface F2. The conductive film 13 is provided on the second main surface F2 side, and the area of ​​the glass substrate 11 in plan view is 0.025 m². 2 That is all. The conductive film 13 is 1.5 × 10 3 It has a sheet resistance value of Ω / □ or less. The sheet resistance value of the conductive film 13 is 1.0 × 10 3 A impedance of Ω / □ or less is more preferable, 500Ω / □ or less is even more preferable, and 200Ω / □ or less is particularly preferable. The vehicle antenna device 1 is capable of receiving AM broadcast waves from a feed point 16 that is electrically connected to the conductive film 13.

[0076] As a result, according to the vehicle antenna device 1 of this embodiment, coatings such as a conductive film for heat reflection (heat reflective film) and a conductive film for low radiation (Low-E coating) can be used as antennas for AM broadcast waves. Therefore, the vehicle antenna device 1 of this embodiment can easily receive AM broadcast waves using the conductive film 13 in vehicle glass 10 (vehicle window glass) that uses the conductive film 13.

[0077] Furthermore, since a larger area of ​​the conductive film 13 makes it easier to obtain antenna gain in the AM broadcast frequency band, the area of ​​the glass substrate 11 in plan view is 0.025 m². 2 The above is preferable. Also, the lower the sheet resistance value of the conductive film 13, the easier it is to obtain antenna gain in the AM broadcast frequency band, so 1.5 × 10 3 A sheet resistance value of Ω / □ or less is preferred. Therefore, the vehicle antenna device 1 of this embodiment can obtain sufficient antenna gain in the AM broadcast frequency band.

[0078] In this embodiment, the power supply point 16 is located in the center of the conductive film 13, at least 150 mm away from the edge of the glass substrate 11 in a plan view of the glass substrate 11. The outer edge of the conductive film 13 is approximately rectangular in a plan view of the glass substrate 11. As a result, the vehicle antenna device 1 of this embodiment can easily receive AM broadcast waves using the conductive film 13, for example, in a roof antenna.

[0079] In this embodiment, the feed point 16 electrically connected to the conductive film 13 is the first feed point. The vehicle antenna device 1 comprises an antenna 21, an antenna electrode 15, an antenna conductor 12, and a high-pass filter 40. The antenna 21 is provided on the first main surface F1 side and receives radio waves of at least one of the frequencies in the VHF band and the UHF band. The antenna electrode 15 is positioned inward from the outer edge of the void region VA within the conductive film 13 in a plan view of the glass substrate 11. The antenna conductor 12 is connected to the antenna 21 and is positioned on the first main surface F1 side. The high-pass filter 40 allows signals of at least one of the frequencies in the VHF band and the UHF band to pass through between the conductive film 13 and the ground conductor, and blocks signals of the AM broadcast wave frequency band. The antenna conductor 12 is electrically connected to the antenna electrode 15. The vehicle antenna device 1 is capable of receiving at least one of the frequencies in the VHF band and the UHF band based on the signal received with the antenna electrode 15 as the second feed point.

[0080] As a result, with the vehicle antenna device 1 of this embodiment, the conductive film 13 can be used as both a receiving antenna (AM antenna) for the AM broadcast frequency band and the antenna ground of the antenna 21, and a large area can be secured as the antenna ground. Therefore, the vehicle antenna device 1 of this embodiment can easily receive AM broadcast waves using the conductive film 13, and can obtain sufficient antenna gain for at least one of the VHF and UHF frequency bands. Furthermore, sufficient antenna gain can be obtained without mechanical processing such as drilling holes in the glass substrate 11 of the antenna 21.

[0081] Furthermore, in this embodiment, the antenna conductor 12 and the antenna electrode 15 are electrically connected by capacitive coupling. As a result, with the vehicle antenna device 1 of this embodiment, the received signal from the antenna 21 can be extracted from the antenna electrode 15 without drilling holes in the glass substrate 11, and the antenna 21 can be installed at any location on the vehicle glass 10.

[0082] Furthermore, in this embodiment, the antenna 21 is capable of receiving FM broadcast wave frequencies. The vehicle antenna device 1 includes an AM amplifier 31 and an FM amplifier 32. A signal in the AM broadcast wave frequency band is input to the AM amplifier 31 from the feed point 16 (first feed point). A signal in the FM broadcast wave frequency band is input to the FM amplifier 32 from the antenna electrode 15 (second feed point). As a result, the vehicle antenna device 1 of this embodiment can appropriately receive signals in both the AM broadcast wave frequency band and the FM broadcast wave frequency band.

[0083] In this embodiment, the high-pass filter 40 is a capacitor C1. The capacitance of capacitor C1 is 5pF to 150pF. More preferably, the capacitance of capacitor C1 is 5pF to 100pF. As a result, the vehicle antenna device 1 of this embodiment can implement a high-pass filter 40 with a simple configuration of a capacitor C1.

[0084] Furthermore, in this embodiment, the antenna 21 is surrounded by an antenna cover 22 (cover member) that protrudes outward from the first main surface F1 side of the glass substrate 11. The dielectric substrate is the glass substrate 11. The glass substrate 11 may be mounted on the roof of the vehicle parallel to the horizontal plane of the vehicle, or it may be applied as a side window or rear window. As a result, with the vehicle antenna device 1 of this embodiment, for example, in the case of a roof glass, sufficient antenna gain can be obtained without mechanical processing of the glass substrate 11.

[0085] [Second Embodiment] Next, with reference to the drawings, a vehicle antenna device 1a of a second embodiment will be described. In this embodiment, a modified example will be described in which the antenna conductor 12a and the antenna electrode 15a are directly connected by a connecting conductor 18.

[0086] Figure 10 is a cross-sectional view showing an example of a vehicle antenna device 1a according to the second embodiment. The perspective view of the vehicle antenna device 1a in this embodiment is the same as that of the first embodiment shown in Figure 1 above, so its description is omitted here. Also, in Figure 10, the configuration of the antenna cover 22 is the same as that of the first embodiment shown in Figure 2, so it is omitted here.

[0087] As shown in Figure 10, the vehicle antenna device 1a comprises a vehicle glass 10a, an amplifier section 30, and a high-pass filter 40. The vehicle glass 10a comprises a glass substrate 11, an antenna conductor 12a, a conductive film 13, an antenna electrode 15a, a feed point 16, a shielding layer 17, and a connecting conductor 18. In Figure 10, components identical to those in the first embodiment shown in Figure 2 are given the same reference numerals, and their descriptions are omitted.

[0088] The connecting conductor 18 is a conductor placed within a through-hole in the glass substrate 11. In this embodiment, the antenna conductor 12a and the antenna electrode 15a are directly connected by a connecting conductor 18. The other configurations of this embodiment are the same as those of the first embodiment shown in Figure 2 above, so their description is omitted here.

[0089] In this embodiment, the AM broadcast frequency band signal is input from the feed point 16 (first feed point) to the AM amplifier 31 of the amplifier section 30. The FM broadcast frequency band signal is input from the antenna electrode 15a (second feed point) to the FM amplifier 32 of the amplifier section 30.

[0090] As described above, in this embodiment, the antenna conductor 12a and the antenna electrode 15a are directly connected by a connecting conductor 18 which is placed in a through-hole in the glass substrate 11. As a result, with the vehicle antenna device 1a of this embodiment, similar to the first embodiment, sufficient antenna gain of the antenna 21 can be obtained with minimal mechanical processing of the glass substrate 11.

[0091] [Third Embodiment] Next, with reference to the drawings, a vehicle antenna device 1b of a third embodiment will be described. In this embodiment, a modified example using laminated glass will be described.

[0092] Figure 11 is a cross-sectional view showing an example of the vehicle antenna device 1b of this embodiment. Note that the perspective view of the vehicle antenna device 1b in this embodiment is the same as that of the first embodiment shown in Figure 1 above, so its description is omitted here. Also, in Figure 11, the configuration of the antenna cover 22 is the same as that of the first embodiment shown in Figure 2, so it is omitted here.

[0093] As shown in Figure 11, the vehicle antenna device 1b comprises a vehicle glass 10b, an amplifier unit 30, and a high-pass filter 40. The vehicle glass 10b is, for example, laminated glass. The vehicle glass 10b comprises two glass substrates 11 (11-1, 11-2), an antenna conductor 12, a conductive film 13, an interlayer 14, an antenna electrode 15, a signal electrode 16a, and a connecting conductor 18a.

[0094] Glass substrate 11-1 (an example of a first dielectric substrate) and glass substrate 11-2 (an example of a second dielectric substrate) are glass substrates for laminated glass bonded together by an interlayer 14. Each of glass substrate 11-1 and glass substrate 11-2 is an example of a dielectric substrate. Glass substrate 11-1 may also be referred to as the first glass substrate, and glass substrate 11-2 may also be referred to as the second glass substrate.

[0095] In this embodiment, the main surface of the glass substrate 11-1 facing the vehicle is the first main surface F1. The main surface opposite to the first main surface F1 is the second main surface F2. The main surface of the glass substrate 11-2 facing the glass substrate 11-1 is the third main surface F3. The main surface opposite to the third main surface F3 is the fourth main surface F4.

[0096] The glass substrate 11-2 is positioned parallel to the second main surface F2 so as to face the second main surface F2 side of the glass substrate 11-1. The conductive film 13 and the interlayer 14 are sandwiched between the glass substrate 11-1 and the glass substrate 11-2. As shown in Figure 11, the conductive film 13 is positioned in contact with the second main surface F2, but it may also be positioned in contact with the third main surface F3.

[0097] Furthermore, the interlayer 14 may have a configuration in which multiple layers are stacked. In this case, the conductive film 13 may be arranged to be inserted between the layers of the multiple interlayer 14. In this case, the conductive film 13 may be a conductor included in a dimmable film whose visible light transmittance can be controlled by applying an AC voltage. The dimmable film has a pair of resin substrates, a pair of ITO (Indium Tin Oxide) films, a transparent conductive polymer, a laminated film of a metal layer and a dielectric layer, silver nanowires, and a conductive film 13 such as a silver or copper metal mesh, and a dimmable layer sandwiched between the pair of conductive films 13. In the dimmable film, the ITO films are provided on the main surface of the resin substrates. Since the main surfaces of the pair of resin substrates face each other, the pair of ITO films also face each other. The dimmable layer is a molecular layer such as a liquid crystal having optical anisotropy. The conductive film 13 may also be a conductive film included in a solar cell panel.

[0098] In Figure 11, the conductive film 13 is shown as a single layer for convenience, but if the conductive film 13 includes a light-adjusting film, the conductive film 13 is a pair of conductive films. Furthermore, the vehicle glass 10b may have a shielding layer 17 (not shown) that blocks visible light, as described in the first embodiment. The shielding layer 17 can be arranged on at least one of the second main surface F2, the third main surface F3, and the fourth main surface F4. The shielding layer 17 may be arranged only on the fourth main surface F4, for example.

[0099] The interlayer 14 is an adhesive layer such as a transparent polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, or a cycloolefin polymer (COP) film. The interlayer 14 is placed between the glass substrate 11-1 and the glass substrate 11-2. The interlayer 14 adheres the glass substrate 11-1, the conductive film 13, and the glass substrate 11-2. A laminated glass is formed by the laminated structure bonded by the interlayer 14.

[0100] In this embodiment, the antenna electrode 15 is positioned inward from the outer edge of the void region VA in a plan view of the glass substrate 11-2(11). The antenna electrode 15 is positioned on the second main surface F2 side and is electrically connected to the antenna conductor 12. The antenna electrode 15 is positioned, for example, in contact with the fourth main surface F4 of the glass substrate 11-2. The antenna electrode 15 is formed to face the antenna conductor 12. The glass substrate 11-1, the interlayer 14, and the glass substrate 11-2 are sandwiched between the antenna electrode 15 and the antenna conductor 12. In this embodiment, the antenna conductor 12 and the antenna electrode 15 are positioned to be electrically connected by capacitive coupling. Here, the antenna electrode 15 functions as a second feed point.

[0101] The glass substrates 11-1, 14, and 11-2 have thicknesses of approximately 2 mm, 1 mm, and 2 mm, respectively. The distance between the antenna conductor 12 and the antenna electrode 15 is approximately 5 mm. For VHF and UHF frequency signals to be capacitively coupled, the distance between the dielectrics between the conductors should be less than 30 mm, preferably 20 mm or less, and more preferably 10 mm or less. As described above, the thickness of the vehicle glass 10b is typically about 5 mm, so the distance between the antenna conductor 12 and the antenna electrode 15 is sufficient for capacitive coupling. Thus, if the thickness of the laminated vehicle glass 10b is less than 30 mm, capacitive coupling between the antenna conductor 12 and the antenna electrode 15 is possible. The circuit can be configured to amplify the signal received by the antenna 21 in the amplifier section 30.

[0102] The signal electrode 16a is an electrode positioned on the fourth main surface F4 side of the glass substrate 11-2 and functions as a feed point for the conductive film 13, which functions as an AM antenna for receiving AM broadcast waves. The signal electrode 16a is positioned to be electrically connected to the conductive film 13 by a connecting conductor 18a. Thus, the signal electrode 16a is positioned to overlap with the conductive film 13 in a plan view of the glass substrate 11-2(11).

[0103] The connecting conductor 18a is a conductor that penetrates the glass substrate 11-2. The connecting conductor 18a electrically connects the conductive film 13 and the signal electrode 16a directly. The other configurations of this embodiment are the same as those of the first embodiment shown in Figure 2 above, so their description is omitted here.

[0104] In this embodiment, the AM broadcast frequency band signal is input from the signal electrode 16a (first feed point) to the AM amplifier 31 of the amplifier section 30. The FM broadcast frequency band signal is input from the antenna electrode 15 (second feed point) to the FM amplifier 32 of the amplifier section 30.

[0105] As described above, in this embodiment, the glass substrate 11 is a glass substrate 11-1 (first dielectric substrate). The vehicle antenna device 1b includes a glass substrate 11-2 arranged parallel to the second main surface F2 on the side of the second main surface F2 of the glass substrate 11-1, and an interlayer 14 arranged between the glass substrate 11-1 and the glass substrate 11-2. The glass substrate 11-2 has a third main surface F3 on the side of the glass substrate 11-1 and a fourth main surface F4 on the opposite side from the third main surface F3. The conductive film 13 is arranged between the glass substrate 11-1 and the glass substrate 11-2, and the antenna electrode 15 is arranged on the side of the fourth main surface F4. The conductive film 13 is arranged, for example, in contact with the second main surface F2.

[0106] As a result, with the vehicle antenna device 1b of this embodiment, even when laminated glass comprising a glass substrate 11-1 (first dielectric substrate) and a glass substrate 11-2 is used, the same effects as those of the first embodiment described above are achieved, and AM broadcast waves can be easily received using the conductive film 13 in the vehicle glass 10b using the conductive film 13. Furthermore, with the vehicle antenna device 1b of this embodiment, sufficient antenna gain can be obtained with minimal mechanical processing of the glass substrate 11 relative to the antenna 21.

[0107] [Fourth Embodiment] Next, with reference to the drawings, a vehicle antenna device 1c of the fourth embodiment will be described. In this embodiment, a modified example will be described in which laminated glass is used and a conductive film 13a, which is a light-adjusting film, is provided.

[0108] Figure 12 is a cross-sectional view showing an example of a vehicle antenna device 1c according to this embodiment. The perspective view of the vehicle antenna device 1c in this embodiment is the same as that of the first embodiment shown in Figure 1 above, so its description is omitted here. Also, in Figure 12, the configuration of the antenna cover 22 is the same as that of the first embodiment shown in Figure 2, so it is omitted here.

[0109] As shown in Figure 12, the vehicle antenna device 1c comprises a vehicle glass 10c, an amplifier unit 30, and a high-pass filter 40. The vehicle glass 10c is, for example, laminated glass. The vehicle glass 10c comprises two glass substrates 11 (11-1, 11-2), an antenna conductor 12, a conductive film 13a, an interlayer 14 (14-1, 14-2), an antenna electrode 15, a signal electrode 16a, and a connecting conductor 18a. In Figure 12, components identical to those in the third embodiment shown in Figure 11 are given the same reference numerals, and their descriptions are omitted.

[0110] In this embodiment, the interlayer 14 includes interlayer 14-1 (first interlayer) and interlayer 14-2 (second interlayer). Interlayers 14-1 and 14-2 are, for example, PVB films, EVA films, or COP films, but it is preferable to use the same material for interlayers 14-1 and 14-2.

[0111] The conductive film 13a is a light-adjusting film containing a conductor. The conductive film 13a is sandwiched between interlayers 14-1 and 14-2. In Figure 12, the conductive film 13a is shown as a single layer for convenience, but when the conductive film 13a includes a light-adjusting film, the conductive film 13a is a pair of conductive films. The conductive film 13a is positioned sandwiched between interlayers 14-1 and 14-2. Furthermore, the connecting conductor 18a in this embodiment is a conductor that penetrates the glass substrate 11-2. The connecting conductor 18a electrically connects the conductive film 13a and the signal electrode 16a directly.

[0112] In this embodiment, the conductive film 13a, which is a light-adjusting film, functions as both an AM antenna and an antenna ground for the antenna 21. The AM broadcast wave frequency band signal received by the conductive film 13a is input from the signal electrode 16a (first feed point) to the AM amplifier 31 of the amplifier unit 30. The FM broadcast wave frequency band signal is input from the antenna electrode 15 (second feed point) to the FM amplifier 32 of the amplifier unit 30. Furthermore, a choke coil 50 is connected to the conductive film 13a, which is a light-adjusting film, to prevent leakage of the AM broadcast wave reception signal.

[0113] As described above, in this embodiment, the interlayer 14 includes interlayer 14-1 (first interlayer) and interlayer 14-2 (second interlayer). The conductive film 13a is sandwiched between interlayer 14-1 and interlayer 14-2. The conductive film 13a is a light-adjusting film containing a conductor.

[0114] As a result, in the vehicle antenna device 1c of this embodiment, the conductive film 13a is arranged between the glass substrate 11-1 (first dielectric substrate) and the glass substrate 11-2 (second dielectric substrate). Therefore, even if the conductive film 13a is a light-adjusting film, for example, the same effects as in the third embodiment described above can be achieved, and in a vehicle glass 10c using a light-adjusting conductive film 13a, AM broadcast waves can be easily received by utilizing the conductive film 13a. Furthermore, in the vehicle antenna device 1c of this embodiment, since the light-adjusting conductive film 13a functions as an antenna ground for the antenna 21, sufficient antenna gain can be obtained with minimal mechanical processing of the glass substrate 11 relative to the antenna 21.

[0115] [Fifth Embodiment] Next, with reference to the drawings, a fifth embodiment of the vehicle antenna device 1d will be described. In this embodiment, a modified example will be described in which laminated glass is used and a conductive film 13b is provided, which is a conductive film for heat reflection (heat reflective film) or a conductive film for low radiation (Low-E coating).

[0116] Figure 13 is a cross-sectional view showing an example of a vehicle antenna device 1d according to this embodiment. Note that the perspective view of the vehicle antenna device 1d in this embodiment is the same as that of the first embodiment shown in Figure 1 above, so its description is omitted here. Also, in Figure 13, the configuration of the antenna cover 22 is the same as that of the first embodiment shown in Figure 2, so it is omitted here.

[0117] As shown in Figure 13, the vehicle antenna device 1d comprises a vehicle glass 10d, an amplifier unit 30, and a high-pass filter 40. The vehicle glass 10d is, for example, laminated glass. The vehicle glass 10d comprises two glass substrates 11 (11-1, 11-2), an antenna conductor 12, a conductive film 13b, an interlayer 14, an antenna electrode 15, a signal electrode 16a, and a connecting conductor 18a. In Figure 13, components identical to those in the third embodiment shown in Figure 11 are given the same reference numerals, and their descriptions are omitted.

[0118] The conductive film 13b is, for example, a conductive film for heat ray reflection (heat ray reflective film) or a conductive film for low emission (Low-E coating). The conductive film 13b is placed between the interlayer 14 and the glass substrate 11-2, in contact with the third main surface F3 of the glass substrate 11-2. Alternatively, the conductive film 13b may be placed in contact with the fourth main surface F4 of the glass substrate 11-2.

[0119] Furthermore, the connecting conductor 18a in this embodiment is a conductor that penetrates the glass substrate 11-2. The connecting conductor 18a electrically connects the conductive film 13b and the signal electrode 16a directly.

[0120] In this embodiment, the conductive film 13b functions as both an AM antenna and an antenna ground for the antenna 21. The AM broadcast wave frequency band signal received by the conductive film 13b is input from the signal electrode 16a (first feed point) to the AM amplifier 31 of the amplifier section 30. The FM broadcast wave frequency band signal is input from the antenna electrode 15 (second feed point) to the FM amplifier 32 of the amplifier section 30.

[0121] As described above, in this embodiment, the conductive film 13b is arranged in contact with the third main surface F3 or the fourth main surface F4. The conductive film 13b is, for example, a conductive film for heat ray reflection (heat ray reflective film) or a conductive film for low emission (Low-E coating).

[0122] As a result, with the vehicle antenna device 1d of this embodiment, even when the conductive film 13b is positioned in contact with the third main surface F3 or the fourth main surface F4, the same effects as those of the third embodiment described above are achieved, and AM broadcast waves can be easily received using the conductive film 13b. Furthermore, in the vehicle antenna device 1d of this embodiment, since the conductive film 13b functions as an antenna ground for the antenna 21, sufficient antenna gain can be obtained with minimal mechanical processing of the glass substrate 11 relative to the antenna 21.

[0123] [Sixth Embodiment] Next, with reference to the drawings, a sixth embodiment of the vehicle antenna device 1e will be described. In this embodiment, a modified example will be described in which laminated glass is used and both a conductive film 13, which is a conductive film for heat reflection (heat reflective film), and a conductive film 13a, which is a light-adjusting film, are included.

[0124] Figure 14 is a cross-sectional view showing an example of a vehicle antenna device 1e according to this embodiment. Note that the perspective view of the vehicle antenna device 1e in this embodiment is the same as that of the first embodiment shown in Figure 1 above, so its description is omitted here. Also, in Figure 14, the configuration of the antenna cover 22 is the same as that of the first embodiment shown in Figure 2, so it is omitted here. Furthermore, a choke coil 50 is connected to the conductive film 13a, which is a light-adjusting film, to prevent leakage of the AM broadcast wave reception signal, similar to the fourth embodiment shown in Figure 12.

[0125] As shown in Figure 14, the vehicle antenna device 1e comprises a vehicle glass 10e, an amplifier unit 30, and a high-pass filter 40. The vehicle glass 10e is, for example, laminated glass. The vehicle glass 10e comprises two glass substrates 11 (11-1, 11-2), an antenna conductor 12, a conductive film 13 and a conductive film 13a, an interlayer 14 (14-1, 14-2), an antenna electrode 15, a signal electrode 16a, and a connecting conductor 18a. In Figure 14, components identical to those in the third and fourth embodiments shown in Figures 11 and 12 are given the same reference numerals, and their descriptions are omitted.

[0126] The conductive film 13 is, for example, a conductive film for heat ray reflection (heat ray reflective film). The conductive film 13 is placed in contact with the second main surface F2 of the glass substrate 11-1. The sheet resistance of the conductive film 13 is, for example, lower than the sheet resistance of the conductive film 13a.

[0127] Furthermore, the conductive film 13a is, for example, a dimmable film containing a conductor. The dimmable film is a dimmable film whose light transmittance can be electrically changed, and comprises, for example, a transparent conductive film such as ITO. In Figure 14, the conductive film 13a is shown as a single layer for convenience, but when the conductive film 13a comprises a dimmable film, the conductive film 13a is a pair of conductive films. The conductive film 13a is sandwiched between interlayer films 14-1 and 14-2. In a plan view of the glass substrate 11-1, the conductive film 13a has a second void region VA2 which is positioned to overlap with the first void region VA1, which is the void region VA of the conductive film 13. In a plan view of the glass substrate 11-1, it is preferable that the outer edges of the first void region VA1 and the outer edges of the second void region VA2 coincide, although a slight misalignment is acceptable.

[0128] In this embodiment, the interlayer 14 comprises an interlayer 14-1 (first interlayer) and an interlayer 14-2 (second interlayer). Interlayers 14-1 and 14-2 are, for example, PVB films, EVA films, or COP films, but it is preferable to use the same material for interlayers 14-1 and 14-2. Furthermore, the connecting conductor 18a in this embodiment is a conductor that penetrates the glass substrate 11-2. The connecting conductor 18a electrically connects the conductive film 13a and the signal electrode 16a directly. Alternatively, the connecting conductor 18a may electrically connect the conductive film 13 and the signal electrode 16a directly.

[0129] In this embodiment, the conductive film 13a, which is a light-adjusting film, or the conductive film 13 for heat reflection, functions as both an AM antenna and an antenna ground for the antenna 21. The AM broadcast wave frequency band signal received by the conductive film 13a (light-adjusting film) or the conductive film 13 for heat reflection is input from the signal electrode 16a (first feed point) to the AM amplifier 31 of the amplifier unit 30. In addition, the FM broadcast wave frequency band signal is input from the antenna electrode 15 (second feed point) to the FM amplifier 32 of the amplifier unit 30.

[0130] As described above, in this embodiment, the interlayer 14 includes interlayer 14-1 and interlayer 14-2, and the conductive film includes conductive film 13 (first conductive film) and conductive film 13a (second conductive film). The conductive film 13 and conductive film 13a are arranged in two of the following positions: on the second main surface F2, between interlayer 14-1 and interlayer 14-2, on the third main surface F3, and on the fourth main surface F4, and are arranged in order from the one closest to the glass substrate 11-1. In a plan view of the glass substrate 11-1, the conductive film 13a has a second void region VA2 that is arranged to overlap with the first void region VA1, which is the void region VA of the conductive film 13.

[0131] As a result, the vehicle antenna device 1e of this embodiment provides the same effects as the third embodiment described above, even when both conductive film 13 and conductive film 13a are provided, and AM broadcast waves can be easily received using either conductive film 13a or conductive film 13. Furthermore, in the vehicle antenna device 1e of this embodiment, since conductive film 13a or conductive film 13 functions as an antenna ground for the antenna 21, sufficient antenna gain can be obtained with minimal mechanical processing of the glass substrate 11 relative to the antenna 21.

[0132] In this embodiment, the conductive film 13 is positioned in contact with the second main surface F2, and the conductive film 13a is sandwiched between the interlayer film 14-1 and the interlayer film 14-2. The conductive film 13 is, for example, a conductor for heat ray reflection (heat ray reflective film), and the conductive film 13a is, for example, a light-adjusting film containing a conductor. As a result, the vehicle antenna device 1e of this embodiment can easily receive AM broadcast waves even if it is equipped with both a heat-reflective conductor (heat-reflective film) and a light-adjusting film.

[0133] [Seventh Embodiment] Next, with reference to the drawings, a seventh embodiment of the vehicle antenna device 1f will be described. In this embodiment, a modified example will be described in which laminated glass is used and both a conductive film 13a, which is a light-adjusting film, and a conductive film 13c, which is a conductor (Low-E coating) for low-emission films, are included.

[0134] Figure 15 is a cross-sectional view showing an example of a vehicle antenna device 1f according to this embodiment. Note that the perspective view of the vehicle antenna device 1f in this embodiment is the same as that of the first embodiment shown in Figure 1 above, so its description is omitted here. Also, in Figure 15, the configuration of the antenna cover 22 is the same as that of the first and fourth embodiments shown in Figures 2 and 12, so it is omitted here.

[0135] As shown in Figure 15, the vehicle antenna device 1f comprises a vehicle glass 10f, an amplifier section 30, and a high-pass filter 40. The vehicle glass 10f is, for example, laminated glass. The vehicle glass 10f comprises two glass substrates 11 (11-1, 11-2), an antenna conductor 12, conductive films 13a and 13c, an interlayer 14, an antenna electrode 15, and a feed point 16. In addition, a choke coil 50 is connected to the conductive film 13a, which is a light-adjusting film, to prevent leakage of the AM broadcast wave reception signal, similar to the fourth embodiment shown in Figure 12. In Figure 15, components identical to those in the first and fourth embodiments shown in Figures 2 and 12 are given the same reference numerals, and their descriptions are omitted.

[0136] The conductive film 13c is, for example, a low-emission conductive film (Low-E coating). The conductive film 13c is placed in contact with the fourth main surface F4 of the glass substrate 11-2. When a Low-E coating is provided on the fourth main surface F4, it is preferable to overcoat it with an insulating layer so that the Low-E coating is not exposed on the surface. The conductive film 13c also has a third void region VA3 which is arranged to overlap with the first void region VA1 in a plan view of the glass substrate 11-1. In a plan view of the glass substrate 11-1, it is preferable that the outer edges of the first void region VA1 and the outer edges of the third void region VA3 coincide, although a slight misalignment is acceptable.

[0137] In this embodiment, the feed point 16 is a part of the conductive film 13c and is electrically connected to the conductive film 13c. The vehicle antenna device 1f can receive AM broadcast waves from the feed point 16. In a plan view of the glass substrate 11-2, the feed point 16 is located in the center of the conductive film 13, at least 150 mm away from the edge of the glass substrate 11-2.

[0138] In this embodiment, the conductive film 13c, which is a low-emission conductive film (Low-E coating), functions as both an AM antenna and an antenna ground for the antenna 21. The AM broadcast wave frequency band signal received by the conductive film 13c (Low-E coating) is input from the feed point 16 (first feed point) to the AM amplifier 31 of the amplifier section 30. In addition, the FM broadcast wave frequency band signal is input from the antenna electrode 15 (second feed point) to the FM amplifier 32 of the amplifier section 30.

[0139] As described above, in this embodiment, the conductive film 13a (first conductive film) is sandwiched between the interlayer film 14-1 and the interlayer film 14-2. The conductive film 13c (second conductive film) is positioned in contact with the fourth main surface F4. The conductive film 13a is, for example, a light-adjusting film containing a conductor. The conductive film 13c is a conductor for low-emission films (Low-E coating). As a result, according to the vehicle antenna device 1f of this embodiment, even if it is equipped with both a dimming film and a conductor for low-emission film (Low-E coating), AM broadcast waves can be easily received.

[0140] [Eighth Embodiment] Next, with reference to the drawings, a vehicle antenna device 1g of the eighth embodiment will be described. In this embodiment, a modified example will be described in which the conductive film 13 and the signal electrode 16b are electrically connected by capacitive coupling.

[0141] Figure 16 is a cross-sectional view showing an example of a vehicle antenna device 1g according to this embodiment. The perspective view of the vehicle antenna device 1g in this embodiment is the same as that of the first embodiment shown in Figure 1 above, so its description is omitted here. Also, in Figure 16, the configuration of the antenna cover 22 is the same as that of the first embodiment shown in Figure 2, so it is omitted here.

[0142] As shown in Figure 16, the vehicle antenna device 1g comprises a vehicle glass 10g, an amplifier section 30, and a high-pass filter 40. The vehicle glass 10g is, for example, laminated glass. The vehicle glass 10g comprises two glass substrates 11 (11-1, 11-2), an antenna conductor 12, a conductive film 13, an interlayer 14, an antenna electrode 15, and a signal electrode 16b. This embodiment differs from the third embodiment described above in that it does not include a connecting conductor 18a. In Figure 16, components identical to those in the third embodiment shown in Figure 11 are given the same reference numerals, and their descriptions are omitted.

[0143] The signal electrode 16b is positioned to be electrically connected to the conductive film 13 by capacitive coupling. That is, the signal electrode 16b is positioned so as to overlap with the conductive film 13 in a plan view of the glass substrate 11-2(11). Furthermore, the signal electrode 16b is formed in a square loop shape in a plan view of the glass substrate 11-2(11). That is, the outer and inner edges of the signal electrode 16b are square.

[0144] In this embodiment, the conductive film 13 functions as both an AM antenna and an antenna ground for the antenna 21. The AM broadcast wave frequency band signal received by the conductive film 13 is electrically connected to the signal electrode 16b (first feed point) by capacitive coupling and input from the feed point 16 (first feed point) to the AM amplifier 31 of the amplifier section 30. In addition, the FM broadcast wave frequency band signal is input from the antenna electrode 15 (second feed point) to the FM amplifier 32 of the amplifier section 30.

[0145] As described above, in this embodiment, the conductive film 13 and the signal electrode 16b are electrically connected by capacitive coupling. As a result, the vehicle antenna device 1g of this embodiment can extract the AM broadcast wave reception signal from the signal electrode 16b (first feed point) without drilling holes in the glass substrate 11-2(11), and can receive AM broadcast waves even more simply by utilizing the conductive film 13.

[0146] The present invention is not limited to the embodiments described above and can be modified without departing from the spirit of the invention. For example, in each of the embodiments described above, the antenna section 20 was described as a shark fin antenna, but it is not limited to this, and for example, it may be a rod antenna.

[0147] Furthermore, although the above embodiments described an example in which the dielectric substrate is a glass substrate 11, the invention is not limited to this, and other dielectric substrates such as plastic substrates (resin substrates) may also be used.

[0148] Furthermore, although the third to eighth embodiments described above describe examples in which the vehicle glass 10b to 10g does not have a shielding layer 17, the third to eighth embodiments may also include a shielding layer 17. Furthermore, although the first and second embodiments described above include an example in which the vehicle glass 10 (10a) is provided with a shielding layer 17, the first and second embodiments may also be provided without the shielding layer 17.

[0149] Furthermore, although examples were described in each of the above embodiments in which the capacitor C1 of the high-pass filter 40 is composed of a capacitor element, the capacitor C1 may also be composed of capacitive coupling between the conductive film 13 (13a, 13b) and the ground line (vehicle body BD), for example using a glass substrate 11. Alternatively, the capacitor C1 may be composed of the overlap between the conductive film 13 (13a, 13b) and the vehicle body BD. In addition, the filter 40 may be configured as a bandstop filter.

[0150] Furthermore, in the vehicle antenna device 1e of the sixth embodiment shown in Figure 14, a third conductive film (not shown) in contact with the fourth main surface F4 of the glass substrate 11-2 may be provided. In this case, the third conductive film in contact with the fourth main surface F4 should be arranged so as not to be in contact with the antenna electrode 15.

[0151] As described above, in the vehicle antenna device 1e, when there is a third conductive film in contact with the fourth main surface F4, the first conductive film, conductive film 13, is a heat-reflective film, the second conductive film, conductive film 13a, is a light-adjusting film (or a conductor contained therein), and the third conductive film is a Low-E coating. When the fourth main surface F4 has a Low-E coating, it is preferable to overcoat it with an insulating layer so that the Low-E coating is not exposed on the surface. Furthermore, when the fourth main surface F4 has a Low-E coating, the connecting conductor 18a may be omitted in Figure 14. Furthermore, the feed point 16 may be provided as part of the Low-E coating, which is the third conductive film (as shown in Figure 15).

[0152] Furthermore, in the vehicle antenna devices 1b of the third embodiment shown in Figure 11 to the vehicle antenna device 1e of the sixth embodiment shown in Figure 14, the antenna conductor 12 and the antenna electrode 15 may be directly connected by a connecting conductor 18 (a connecting conductor as shown in the second embodiment) arranged in a through hole in the glass substrate 11. As a result, with vehicle antenna devices 1b to 1e, sufficient antenna gain of the antenna 21 can be obtained with minimal mechanical processing of the glass substrate 11, similar to the first embodiment. [Explanation of Symbols]

[0153] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g Vehicle antenna device 10, 10a, 10b, 10c, 10d, 10e, 10f, 10g Vehicle glass 11, 11-1, 11-2 Glass substrate 12, 12a, 12b Antenna conductors 13, 13a, 13b, 13c conductive film 14, 14-1, 14-2 Interlayer 15, 15a Antenna electrodes 16 Power supply point 16a, 16b signal electrode 17 Shielding layer 18, 18a Connecting conductors 20 Antenna section 21 Antennas 22 Antenna cover 30 Amplifier section 31 AM Amplifier 32 FM amplifier 33 Signal mixer 40 (High-Pass) Filter BD Vehicle Body C1, C2 Capacitors CB coaxial cable F1 First Main Surface F2 Second Main Surface F3 Third Main Surface F4 Fourth Main Surface VA vacancy area VA1 1st vacancy area VA2 2nd vacancy area

Claims

1. A dielectric substrate having a first main surface and a second main surface, A conductive film provided on the second main surface side, the area of ​​the dielectric substrate in a plan view being 0.025 m2 or more, Equipped with, The conductive film has a sheet resistance value of 1.5 × 10³ Ω / □ or less. AM broadcast waves can be received from the power supply point electrically connected to the conductive film. The power supply point is located in the central part of the conductive film, at a distance of 150 mm or more from the edge of the dielectric substrate in a plan view of the dielectric substrate. Vehicle antenna device.

2. The outer edge of the conductive film is approximately rectangular in a plan view of the dielectric substrate. The vehicle antenna device according to claim 1.

3. A dielectric substrate having a first main surface and a second main surface, A conductive film provided on the second main surface side, having a planar area of ​​0.025 m² or more of the dielectric substrate, An antenna provided on the first main surface side for receiving radio waves of at least one of the frequencies in the VHF band and the UHF band, In a plan view of the dielectric substrate, an antenna electrode is positioned inside the outer edge of the vacancy region within the conductive film, An antenna conductor connected to the antenna and positioned on the first main surface side, A filter is provided between the conductive film and the ground conductor that allows signals in at least one of the frequency bands of radio waves in the VHF band and the UHF band to pass through, and blocks signals in the frequency band of AM broadcast waves. Equipped with, The conductive film has a sheet resistance of 1.5 × 10³ Ω / □ or less. AM broadcast waves can be received from the power supply point electrically connected to the conductive film. The power supply point electrically connected to the conductive film is the first power supply point. The antenna conductor is electrically connected to the antenna electrode, The antenna electrode, with the second feed point used as the signal, can receive at least one of the frequencies in the VHF band and the UHF band. Vehicle antenna device.

4. The antenna conductor and the antenna electrode are electrically connected by capacitive coupling. The vehicle antenna device according to claim 3.

5. The antenna conductor and the antenna electrode are directly connected by a connecting conductor placed in a through-hole in the dielectric substrate. The vehicle antenna device according to claim 3.

6. The dielectric substrate is a first dielectric substrate, A second dielectric substrate is arranged parallel to the second main surface on the second main surface side of the first dielectric substrate, An interlayer disposed between the first dielectric substrate and the second dielectric substrate and Equipped with, The second dielectric substrate has a third main surface on the side of the first dielectric substrate and a fourth main surface on the side opposite to the third main surface. The conductive film is disposed between the first dielectric substrate and the second dielectric substrate. The antenna electrode is arranged on the fourth main surface side. The vehicle antenna device according to any one of claims 3 to 5.

7. The conductive film is disposed in contact with the second main surface. The vehicle antenna device according to claim 6.

8. The aforementioned interlayer includes a first interlayer and a second interlayer. The conductive film is sandwiched between the first interlayer and the second interlayer. The vehicle antenna device according to claim 6.

9. The conductive film is a light-adjusting film containing a conductor. The vehicle antenna device according to claim 8.

10. The conductive film is disposed in contact with the third main surface or the fourth main surface. The vehicle antenna device according to claim 6.

11. The aforementioned interlayer includes a first interlayer and a second interlayer. The conductive film includes a first conductive film and a second conductive film. The first conductive film and the second conductive film are arranged at two of the following positions: on the second main surface, between the first and second interlayer films, on the third main surface, and on the fourth main surface, and are arranged in order from the one closest to the first dielectric substrate. The second conductive film has a second vacancy region that, in a plan view of the first dielectric substrate, is arranged to overlap with the first vacancy region, which is the vacancy region of the first conductive film. The vehicle antenna device according to claim 6.

12. The first conductive film is positioned in contact with the second main surface, The second conductive film is sandwiched between the first interlayer and the second interlayer. The vehicle antenna device according to claim 11.

13. The first conductive film is a conductor for heat ray reflection, The second conductive film is a light-adjusting film containing a conductor. The vehicle antenna device according to claim 12.

14. The conductive film includes a third conductive film that is positioned in contact with the fourth main surface. The aforementioned third conductive film is a conductor for low-emission films. The vehicle antenna device according to claim 13.

15. The first conductive film is sandwiched between the first interlayer and the second interlayer. The second conductive film is disposed in contact with the fourth main surface. The vehicle antenna device according to claim 11.

16. The first conductive film is a light-adjusting film containing a conductor, The second conductive film is a conductor for low-emission films. The vehicle antenna device according to claim 14.

17. The aforementioned antenna is capable of receiving FM broadcast frequencies. Including AM amplifiers and FM amplifiers, A signal in the frequency band of an AM broadcast wave is input to the AM amplifier from the first power supply point. A signal in the frequency band of an FM broadcast wave is input to the FM amplifier from the second feed point. The vehicle antenna device according to any one of claims 3 to 5.

18. The aforementioned filter is a capacitor, The capacitance of the aforementioned capacitor is 5pF to 150pF. The vehicle antenna device according to any one of claims 3 to 5.

19. The antenna is arranged surrounded by a cover member that protrudes outward from the first main surface side of the dielectric substrate. The vehicle antenna device according to any one of claims 3 to 5.

20. The dielectric substrate is a glass substrate. The vehicle antenna device according to claim 1.

21. The dielectric substrate is mounted on the roof of the vehicle, parallel to the horizontal plane of the vehicle. The vehicle antenna device according to claim 1.

Images