JP2002368514A - Glass antenna device for vehicles - Google Patents

Abstract

(57) Abstract: Provided is a glass antenna device for a vehicle, which has good characteristics in a high frequency band and can be shared or coexist with a conductive film for electric heating. A planar rectangular antenna conductor (2) is provided on a bonding surface of a front window glass (1) of a glass plate formed of laminated glass or on an inner surface of a vehicle, and a feed point (3) and a contact point are provided on or near the antenna conductor (2). Point 4 is established. The feeding point 3 is connected via a conductor to an amplifier 8 constituting an excitation unit, and the amplifier 8 is connected to a communication device 9 including a receiver or a transceiver. The ground point 4 is connected to the ground of the vehicle via a conductor. The antenna conductor 2 is formed of a transparent conductive film that can be used in common with or coexist with the conductive film for electric heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass antenna device for a vehicle installed on a front window glass of a vehicle such as an automobile.

[0002]

2. Description of the Related Art In recent years, vehicles such as automobiles have been provided with AM / FM.
In addition to radio and TV antennas, GPS (Global Positioning System) and VICS (Vehicle Information and Communication System) used in car navigation systems
An antenna for wireless communication for stem) is mounted. Recently, ETC (Electr
Communication equipment and antennas for the onic Toll Collection System (non-stop automatic toll collection system) are also being installed. A window glass such as a rear glass of such a vehicle is provided with a conductive film of a defroster for anti-fog, a conductive film of an antenna element of an AM / FM radio or a TV, etc., and a glass antenna device is often used. Have been.

[0003] As an antenna for the GPS, VICS, ETC, and the like, a low-profile antenna having a built-in flat antenna or microstrip antenna is used. They were placed on the dashboard in the car or attached to the inside of the window glass.

[0004]

[Problems to be Solved by the Invention] Automotive GPS and VIC
Conventionally, a low-profile antenna as described above has been used as a microwave band or millimeter wave band high-frequency antenna used for S, ETC, and the like, and has been installed outside or inside a vehicle. When installed outside the vehicle, there is a risk of dirt, damage, theft, and the like, and the appearance is not very favorable.

On the other hand, when a low-profile antenna is installed in a vehicle, when a radio wave passes through a glass plate having a relative dielectric constant of 6 to 7 when the radio wave is transmitted, the radio wave after passing through the glass plate repeats multiple reflections and becomes mutually reciprocal. However, there is a problem that the radio waves reflected by the dashboard or the antenna body are reflected again on the glass surface, and the reflected waves and the direct waves are likely to cause phase interference. When a conductive film such as a defroster for anti-fog is provided on a window glass plate such as a front window glass, and a low-profile antenna is installed near the inside of the window glass, high-frequency radio waves are shielded and attenuated by the conductive film. As a result, there is a problem that the receiving efficiency is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a glass antenna device for a vehicle which can obtain good characteristics in a high frequency band and can be shared or coexist with a conductive film for electric heating.

[0007]

According to the present invention, a planar antenna conductor is provided on a bonding surface of a laminated glass provided on a vehicle or on an inner surface of the vehicle, and an excitation is performed on or near the antenna conductor to excite the antenna conductor. Provided is a glass antenna device for a vehicle, characterized in that a feed point for connecting means by direct connection or capacitive coupling is provided.

Preferably, the antenna conductor includes:
The laminated glass is constituted by a conductive film provided on at least a part of the laminated glass. Preferably, a grounding point connected to the ground of the vehicle is further provided on or near the antenna conductor. Preferably, a directivity adjusting conductor for adjusting directivity in cooperation with the antenna conductor is provided in the vehicle.

As described above, a planar antenna conductor is provided on the bonding surface of the laminated glass used for the window glass of the vehicle or on the inner surface of the vehicle and connected to the excitation means, thereby preventing problems such as phase interference. Good characteristics can be obtained in a high frequency band. Further, by forming the antenna conductor with a conductive film, the antenna conductor can be used in common or coexist with a conductive film for electric heating provided on a window glass or the like.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing the configuration of the vehicular glass antenna device according to the first embodiment of the present invention.

In this embodiment, an example in which an antenna element is provided on a front window glass of an automobile to constitute a glass antenna device for a vehicle will be described. The invention is not limited to the front window glass, and any other glass plate installed in a vehicle can be applied as appropriate.

The glass antenna device for a vehicle according to the present embodiment is configured by providing a planar rectangular antenna conductor 2 on a front window glass 1 of a glass plate formed of laminated glass.
A feed point 3 and a ground point 4 are provided on or near the antenna conductor 2. The antenna conductor 2 may be formed of a conductive film, or may be a silver print obtained by baking a silver paste. Further, the shape and arrangement position of the antenna conductor 2 can be arbitrarily configured. Feeding point 3 and grounding point 4
Is appropriately adjusted in order to improve communication performance according to the frequency of the radio wave used.

FIG. 2 is a side view showing a first example of a power supply structure in the glass antenna device for a vehicle according to the present embodiment.
The front window glass 1 is formed using a laminated glass having an outer plate 5, an intermediate film 6, and an inner plate 7. The laminated glass is formed by sandwiching a synthetic resin intermediate film 6 between an outer plate 5 and an inner plate 7 of a glass plate, and pressing and bonding. In FIG. 2 and FIGS. 3, 4, and 7, which will be described later, the components of the front window glass 1 made of laminated glass are drawn apart for convenience, but they are actually in close contact.

The antenna conductor 2 is arranged on the bonding surface between the intermediate film 6 of the front window glass 1 and the inner plate 7. Feeding point 3
The grounding point 4 is installed on the inner surface side of the inner plate 7 and is connected to the antenna conductor 2 by capacitive coupling. In the vehicle, an amplifier 8 for amplifying a reception signal or a transmission signal
And a communication device 9 including a receiver, a transmitter, or a transceiver. Note that the amplifier 8 may be appropriately housed in a housing and installed in a vehicle as an excitation device constituting an excitation unit.

The feeding point 3 is connected to an input terminal (antenna terminal) of the amplifier 8 by a conductor 21 such as an inner conductor of a coaxial cable, and an output terminal (device connection terminal) of the amplifier 8 is connected via a signal line 23 to the communication device 9. Is connected to On the other hand, the ground point 4 is connected to the ground of a vehicle such as a metal body by a conductor 22 such as an outer conductor of a coaxial cable. A reception signal such as a microwave received by the antenna conductor 2 is amplified by an amplifier 8 and then input to a communication device 9 to be demodulated. The transmission signal output from the communication device 9 is amplified by the amplifier 8 and then sent to the antenna conductor 2 to be radiated as radio waves to an external space.

FIG. 3 is a side view showing a second example of the power supply structure in the glass antenna device for a vehicle according to the present embodiment.
The same components as those in the first example shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. Antenna conductor 2 is front window glass 1
The power feeding point 3 and the grounding point 4 are disposed on the antenna conductor 2 on the vehicle inner surface side. In the inner plate 7, insertion holes 7a, 7 for inserting conducting wires 21, 22 connected to the feeding point 3 and the grounding point 4, respectively.
b is provided. The feeding point 3 is connected to the amplifier 8 through the insertion hole 7a by a conductor 21 such as an inner conductor of a coaxial cable. On the other hand, the ground point 4 is connected to the ground of the vehicle through the insertion hole 7b by a conductor 22 such as an outer conductor of a coaxial cable.

FIG. 4 is a side view showing a third example of the power supply structure in the glass antenna device for a vehicle according to the present embodiment.
The same components as those in the first example shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. Antenna conductor 2 is front window glass 1
The power feeding point 3 and the grounding point 4 are provided on the antenna conductor 2 on the vehicle interior surface side. The feed point 3 is connected to the amplifier 8 by a conductor 21 such as the inner conductor of a coaxial cable, and the ground point 4 is connected to the vehicle ground by a conductor 22 such as the outer conductor of the coaxial cable.

The antenna conductor 2 has a function of receiving radio waves arriving from outside the vehicle and / or a function of radiating radio waves outside the vehicle, and is connected to the communication device 9 via a conductor such as a coaxial cable. The antenna conductor 2 is preferably a planar antenna for convenience of attachment and storage.
Further, the planar antenna is preferably a dipole antenna rather than a monopole antenna because of its excellent communication characteristics. Note that the antenna conductor 2 can be used as a monopole antenna without providing the ground point 4. Among the bipolar antennas, a microstrip antenna having excellent communication characteristics is preferable. In microwave communications, communication interference is likely to occur due to radio wave interference, so it is common to use circularly polarized waves that are not easily affected by radio wave interference as communication radio waves. This is because it has excellent communication characteristics. Here, the microstrip antenna is a rectangular substrate having a rectangular shape on a dielectric substrate on which a ground conductor is provided.
Patch radiation conductor (strip) such as circular or elliptical
And an antenna having directivity in a direction substantially perpendicular to the surface of the dielectric substrate on which the patch radiation conductor is provided.

In the example shown in FIG. 1, a microstrip antenna is used as a planar antenna with the antenna conductor 2, and this planar antenna has a radiating conductor (not shown), a feeding point 3, a ground conductor (not shown), And a grounding point 4 connected to the grounding conductor.

When a bipolar antenna is used as the planar antenna, the feed point 3 is connected to the inner conductor of the coaxial cable, and the ground point 4 is connected to the outer conductor of the coaxial cable. On the other hand, when a monopole antenna is used as the planar antenna, since the planar antenna has a radiation conductor and a feed point on the dielectric substrate, the feed point 3 and the inner conductor of the coaxial cable are connected, and the metal body is Connect the outer conductor of the coaxial cable.

The communication device 9 is a transmitter, a receiver, or a transceiver in which the transmitter and the receiver are integrated (for both transmission and reception). When a dipole antenna is used as a planar antenna, the electromotive voltage between the feed point and the ground point is sent to the receiver at the time of reception, and the transmission signal is sent between the feed point and the ground point at the time of transmission. Apply. When a monopole antenna is used as a planar antenna, a reception signal based on a voltage generated at a feeding point is sent to a receiver at the time of reception, and a transmission signal is applied to the feeding point at the time of transmission.

The dimension (length of the vertical or horizontal conductor) L of the antenna conductor 2 is λ _M , the wavelength of the center frequency of the desired frequency band to be used, and the relative dielectric constant (6 to 7) of the glass. _Assuming that the wavelength reduction rate is K, it is preferable that L = (λ _M / 4) × K to (λ _M ) × K. Here, the shortening rate K is usually about 0.64 or around. When the value is within this range, the sensitivity of the desired frequency band to be used is improved by about several dB as compared with the case where the value is outside the range. The antenna conductor 2
Is within a range of about ± 30% over the upper and lower limits of the range of the dimension L.

The glass antenna device for a vehicle configured as described above can be installed at a part of a window glass plate such as a front window glass of an automobile, so that the antenna can be installed at a suitable position in the vehicle. If the antenna conductor 2 is formed of a transparent conductive film or the like, the antenna conductor 2 is inconspicuous and has a good appearance. Also,
Since the antenna conductor 2 is arranged in close contact with the inside of the window glass or the inner side of the window glass in contact with the outside world, the radio wave does not cause phase interference due to multiple reflections or the like, and the reception sensitivity characteristics in a high frequency band such as a microwave. Good characteristics are obtained with respect to, for example.

Further, the antenna conductor 2 of the present embodiment can be commonly used in a plurality of frequency bands. For example,
By changing the configuration of the excitation unit so that the positions of the feeding point and the grounding point are different by using the antenna conductor 2 in common, the antenna can be used in correspondence with different frequency bands.

The frequency band used in the glass antenna apparatus for a vehicle according to the present embodiment is the Japanese FM broadcasting band (76
~ 90MHz), FM broadcast band in the United States (88 ~ 108MHZ)
z), TV VHF band (90-108 MHz, 170-
222MHz), TV UHF band (470-770MHz)
z), North American and European TV VHF bands (45-86 MHz)
z, 175-225 MHz), 800M for car phones
Hz band (810-960 MHz), 1.
5GHz band (1.429-1.501GHz), UHF
Band (300MHz-3GHz), GPS (Global Posit
ioning System) GPS signals from satellites (1575.4)
2MHz), VICS (Vehicle Information and Comm)
unication System) (2.5 GHz), ETC communication (El
ectronicToll Collection System: Nonstop automatic toll collection system (transmission frequency is 5.795 GHz or 5.805 GHz, reception frequency is 5.835 GHz or 5.845 GHz), dedicated narrow area communication (DSRC: De)
dicated Short Range Communication) (915MHz
Band, 5.8 GHz band, 60 GHz band), microwave (1
GHz to 3 THz) and millimeter waves (30 to 300 GHz).

FIG. 5 is a front view showing a configuration of a glass antenna device for a vehicle according to a second embodiment of the present invention. The same components as those of the first embodiment shown in FIG.

The front window glass 1 is provided with an electrically conductive film 12 for fogging prevention over substantially the entire surface except for the peripheral portion, and constitutes an EHW (Electrothermal Windshield). The electric heating conductive film 12 is formed of a transparent conductive film that transmits visible light. A DC power supply 11 and a ground of the vehicle are connected to the conductive film 12 for electric heating, and a DC voltage is applied from the DC power supply 11. As a result, the electrically conductive film 12 generates heat, and the front window glass 1 is heated to prevent dew condensation, thereby preventing fogging.

As the conductive film 12 for electric heating, a conductive thin film (heat ray reflecting film) having a function of reflecting heat rays can be used. The conductive thin film refers to a metal thin film, a metal oxide thin film, or a metal nitride thin film. The metal thin film refers to a thin film containing a metal, but may be a thin film containing a metal oxide and / or a metal nitride in addition to the metal.

The conductive film for electric heating 12 is the antenna conductor 2.
The power supply point 3 and the ground point 4 are provided on or near the electroconductive conductive film 12. Feeding point 3
Is connected to the amplifier 8 by a wire, and the ground point 4 is connected to the vehicle ground by a wire. This antenna conductor 2
In the electric heating conductive film 12 that is shared with the power supply, a DC cut capacitor 10 is inserted between the feeding point 3 and the amplifier 8 and between the ground point 4 and the ground.

In the glass antenna device for a vehicle according to the second embodiment configured as described above, an antenna conductor is provided on a window glass plate such as a front window glass of an automobile, and is used in common with a conductive film for electric heating for anti-fog. Thus, similarly to the first embodiment, the antenna can be installed at a suitable position in the vehicle, and good characteristics such as reception sensitivity characteristics in a high frequency band can be obtained.

FIG. 6 is a front view showing the structure of a glass antenna device for a vehicle according to a third embodiment of the present invention. The same components as those of the first embodiment shown in FIG.

The front window glass 1 is provided with an anti-fogging electric heating conductive film 12 formed of a transparent conductive film over substantially the entire surface except for the peripheral portion, and constitutes an EHW (Electrothermal Windshield). are doing. DC power supply 1 is applied to conductive film 12 for electric heating.
1 is connected to the ground of the vehicle, and a DC voltage is applied from a DC power supply 11. In addition, a part (one corner (here, lower right corner)) of the electroconductive film 12 is cut out,
A rectangular antenna conductor 2 is formed by the cut conductive film, and an antenna is provided on the front window glass 1. Between the conductive film 12 for electric heating and the antenna conductor 2,
Write released lambda _M / 2 or more in order to prevent the loss due to electromagnetic coupling is preferred. A feed point 3 and a ground point 4 are provided on or near the antenna conductor 2. The feed point 3 is connected by a conductor to the amplifier 8 and the ground point 4 is connected by a conductor to the vehicle ground.

In the vehicle glass antenna device according to the third embodiment having the above-described configuration, an antenna conductor is provided on a part of a window glass plate such as a front window glass of an automobile to form an anti-fog electric heating conductive film. By coexisting, as in the first embodiment, the antenna can be installed at a suitable position in the vehicle, and good characteristics in the high frequency band with respect to the reception sensitivity characteristics and the like can be obtained.

FIG. 7 is a side view showing a configuration of a vehicle glass antenna device according to a fourth embodiment of the present invention. FIG.
The same components as those of the first embodiment shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The antenna conductor 2 is arranged between the intermediate film 6 of the front window glass 1 and the inner plate 7, and has a feed point 3 and a ground point 4.
Are installed on the inner surface side of the inner plate 7 and are connected to the antenna conductor 2 by capacitive coupling. An excitation device 14 that accommodates an amplifier 8 for amplifying a reception signal or a transmission signal and constitutes an excitation unit is provided in the vehicle. The excitation device 14 has a planar directivity for changing and adjusting the directivity of an antenna. An adjustment conductor 13 is provided. Although the directivity adjusting conductor 13 is not grounded in the illustrated example, it may be grounded if necessary. It is more effective to provide the directivity adjusting conductor 13 on the innermost side of the vehicle in the excitation device 14 (at the position farthest from the antenna conductor 2). The size, shape, position, and mounting angle of the directivity adjusting conductor 13 are appropriately adjusted to obtain desired characteristics.

Also in the vehicle glass antenna device of the fourth embodiment configured as described above, by providing it on a window glass plate such as a front window glass of an automobile, similar to the first embodiment, a suitable antenna in a vehicle is provided. Antenna can be installed in the position,
Good characteristics can be obtained in a high frequency band with respect to the reception sensitivity characteristics and the like. Further, in the fourth embodiment, by additionally providing the directivity adjusting conductor 13, the sensitivity toward the inside of the vehicle is reduced, so that noise from the inside of the vehicle is hardly received.
Since the launch angle of the antenna can be adjusted, communication characteristics can be further improved.

[0037]

As described above, according to the present invention, an antenna can be installed at a suitable position in a vehicle by providing an antenna conductor on a window glass plate such as a front window glass of an automobile, and the antenna can be installed in a high frequency band. Antenna characteristics such as high receiving sensitivity can be obtained. Further, by changing the configuration of the excitation unit, different frequency bands can be handled by the common antenna conductor. Further, the antenna conductor can be used in common with or coexist with the electroconductive film provided on the window glass. Further, by providing the directivity adjusting conductor near the antenna conductor, desired directivity characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a vehicular glass antenna device according to a first embodiment of the present invention.

FIG. 2 is a side view showing a first example of a power supply structure in the glass antenna device for a vehicle according to the present embodiment.

FIG. 3 is a side view showing a second example of the power supply structure in the glass antenna device for a vehicle according to the present embodiment.

FIG. 4 is a side view showing a third example of the power feeding structure in the glass antenna device for a vehicle according to the present embodiment.

FIG. 5 is a front view showing the configuration of a glass antenna device for a vehicle according to a second embodiment of the present invention.

FIG. 6 is a front view showing the configuration of a glass antenna device for a vehicle according to a third embodiment of the present invention.

FIG. 7 is a side view showing a configuration of a vehicle glass antenna device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front window glass 2 Antenna conductor 3 Feeding point 4 Grounding point 5 Outer plate 6 Intermediate film 7 Inner plate 8 Amplifier 9 Communication device 10 Capacitor 11 DC power supply 12 Conductive conductive film 13 Directivity adjusting conductor 14 Exciting device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuo Teratani 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Koji 1 Asahi Takeji-cho, Chita-gun, Aichi Prefecture Asahi Glass Co., Ltd. (72) Inventor Kenichi Ishii 1 Asahi, Taketoyo-cho, Chita-gun, Aichi Prefecture Asahi Glass Co., Ltd. F-term (reference) 5J046 AA04 AB17 PA07 QA02

Claims (1)

[Claims] 1. A planar antenna conductor is provided on an adhesive surface of a laminated glass provided on a vehicle or on an inner surface of a vehicle, and excitation means for exciting the antenna conductor is directly connected or capacitively coupled on or near the antenna conductor. A glass antenna device for a vehicle, wherein a feeding point to be connected is provided.