JP2001156521A - Glass antenna system for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass antenna system for automobile small is size, low in cost and capable of excellently receiving both long wave and FM broadcast bands. SOLUTION: In the glass antenna system for automobile, series resonance is generated by using the impedance of a defogger 90 and an inductance of a coil 31 placed between the defogger 90 and a receiver 7, parallel resonance is generated by using the impedance of the defogger 90 and vehicle body grounding and a capacitor 32 for the parallel resonance is electrically connected between the defogger and the vehicle body grounding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a long wave broadcasting band (LW).
Band) (150-280 kHz), FM broadcast band in Japan (7
6-90 MHz), US FM broadcast band (88-108M)
The present invention relates to a high-sensitivity, low-noise, and low-cost automotive glass antenna device suitable for reception at, for example, Hz.

[0002]

2. Description of the Related Art Conventionally, a glass antenna device for a vehicle shown in FIG. 10 has been proposed as a glass antenna device for a vehicle in which sensitivity is improved by utilizing resonance (Japanese Utility Model Publication No. 4-530).
70). In this conventional example, a rear window glass plate 81 of an automobile is used.
Is provided with a defogger 79 comprising a heater wire 82 and bus bars 15a, 15b, 15c. A lower bus bar 15a and an upper bus bar 15b are provided on the left side of the defogger 79. The upper bus bar 15b is connected to the vehicle body ground,
The lower bus bar 15a is connected to the anode of the DC power supply 78. The supplied current flows in a U-shape from the lower bus bar 15a to the upper bus bar 15b through the right bus bar 15c. The defogger 79 shown in FIG. 10 has a so-called U-shape.

In the automotive glass antenna device shown in FIG. 10, a choke coil 76 is connected between the bus bars 15a and 15b and a DC power supply 78 for a defogger 79 to increase the impedance of the choke coil 76 in a high frequency band. Thus, a DC current flows from the DC power supply 78 to the defogger 79, but a current in a high frequency band such as a broadcast band is cut off, and the defogger 79 is used as an antenna.

In the medium-wave broadcasting band, defoggers 7
9, a stray capacitance with respect to ground (hereinafter simply referred to as a stray capacitance), a coil 71 and a choke coil 76 cause parallel resonance, and a coil 72, a capacitor 73 and a resistor 74 allow a reception signal in the medium-wave broadcasting band to pass. ing. In addition,
75 is a receiver, and 77 is a noise cut capacitor. In the conventional example of FIG. 10, by adopting such a configuration, sensitivity is improved and noise is reduced.

[0005] However, in order to use this conventional example for receiving a long wave broadcast band, if it is attempted to make parallel resonance in the long wave broadcast band,
The inductance value of each of the coil 71 and the choke coil 76 is too large, about 5 to 20 mH, so that the dimensions of each of the coil 71 and the choke coil 76 cannot be reduced, and the coil 71 and the choke coil 76 are used for each. There is a problem that the cost is increased because the conductor wire needs to be thick and long.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to provide a high-sensitivity and low-noise automotive glass antenna device which can be reduced in size and cost.

[0007]

According to the present invention, there is provided an electric heating type defogger having a heater wire and a bus bar for supplying power to the heater wire, and an antenna conductor provided on a rear window glass plate of an automobile. And a DC power supply, and between the bus bar and the vehicle body ground, a glass antenna device for an automobile in which a choke coil is connected to at least one, comprising a series resonance coil and a parallel resonance capacitor, A series resonance including the defogger impedance and the inductance of the series resonance coil as a resonance element is generated, and a parallel resonance including the defogger impedance and the inductance of the choke coil as the resonance element is generated. The received signal of the band is sent from the defogger to the receiver, and The signal is sent from the antenna conductor to the receiver, and the resonance frequency of the series resonance and the resonance frequency of the parallel resonance are the frequencies at which the sensitivity of the long wave broadcasting band is improved, and the parallel resonance between the defogger and the vehicle body ground. A glass antenna device for an automobile, wherein the capacitor is electrically connected.

Further, an electrically heated defogger having a heater wire and a bus bar for supplying power to the heater wire, and an antenna conductor are provided on a rear window glass plate of the automobile, and are provided between the bus bar and the DC power supply. A choke coil is connected to at least one of the bus bar and the vehicle body ground, and a received signal of the antenna conductor is sent to the receiver. Are electrically connected via wiring and / or circuit elements, and a capacitor for parallel resonance is wired between at least one of between the defogger and the vehicle body ground and between the antenna conductor and the vehicle body ground. as well as/
Another object of the present invention is to provide a glass antenna device for an automobile, wherein the glass antenna device is electrically connected via a circuit element.

[0009]

FIG. 1 shows a rear window glass plate 1 of an automobile.
FIG. 1 is a configuration diagram of an embodiment of a glass antenna device for a vehicle of the present invention that uses the present invention. In FIG. 1, 2 is a heater wire, 3
Is an antenna conductor, 4 is a feed point of the antenna conductor 3, 5a,
5b is a bus bar, 6 is a resonance circuit, 6a and 6b are resonance circuits 6.
6c is the output of the resonance circuit 6, 7 is the receiver, 7a
Is a cable, 8 is a filter circuit, 9 is a choke coil,
10 is a DC power supply, 11 is a capacitor, 20 and 21 are damping resistors, 31 is a series resonance coil, 32 is a parallel resonance capacitor, 47 is a resistor for reducing automobile noise such as engine noise, 48, 49 is a damping resistor, 50 and 51 are DC cut capacitors, 52 is a high-frequency choke coil, 90 is a defogger, and 91 is a feed point provided at the end of a lead wire connected to the defogger 90. In the following description, directions refer to directions in the drawings unless otherwise specified.

In FIG. 1, an electrically heated defogger 90 having a heater wire 2 and bus bars 5a and 5b for supplying power to the heater wire 2 and an antenna conductor 3 are provided on a rear window glass plate 1 of an automobile. . The bus bar 5b and the DC power supply 1
0, and between the bus bar 5a and the vehicle body ground, the choke coil 9 is connected. In order to improve sensitivity and reduce noise, it is preferable to connect as shown in FIG. However, between the bus bar 5b and the DC power supply 10, or
The choke coil 9 may be connected to one side between the bus bar 5a and the vehicle body ground.

In FIG. 1, signals received by the antenna conductor 3 and the defogger 90 are sent to the receiver 7, and a coil 31 for series resonance is wired between the defogger 90 and the receiver 7, a high-frequency choke coil 52, They are electrically connected via a resistor 47 and a capacitor 51. The connection of the series resonance coil 31 is not limited to the configuration of FIG.
It is sufficient that the series resonance coil 31 is electrically connected between the defogger 90 and the receiver 7 via at least one of a wiring and a circuit element.

Here, the circuit element means all elements used for circuits and semiconductors such as capacitors, coils, resistors, diodes, transistors and the like. In addition, wiring means not only electrically connecting with an electric wire but also electrically connecting with a conductor pattern or a connector provided on a circuit board. In FIG. 1, the antenna conductor 3 and the defogger 90 are connected to each other. The fact that "the antenna conductor 3 and the defogger 90 are electrically connected" due to capacitive coupling is not included in the wiring. The same applies hereinafter.

In FIG. 1, a capacitor 32 for parallel resonance is connected between a defogger 90 and the vehicle body ground by a wiring and a resistor 48.
Are electrically connected via The connection of the capacitor 32 for parallel resonance is not limited to the configuration shown in FIG. 1, and the capacitor 32 for parallel resonance is electrically connected between the defogger 90 and the vehicle body ground via at least one of a wiring and a circuit element. It should just be. Note that the vehicle body ground refers to a conductive portion of the vehicle body and is usually a metal portion.

FIG. 3 is an equivalent circuit diagram for explaining the principle of the apparatus shown in FIG. However, the resistance 47, the resistance 48 and the resistance 4
Reference numeral 9 is omitted for simplicity of description, and the locations of the resistors 47 and 48 are short-circuited and the locations of the resistor 49 are open. In FIG. 3, E1 is a voltage power supply of the antenna conductor 3,
E2 is the voltage power supply of the defogger 90, 33 is the stray capacitance of the antenna conductor 3, 34 is the stray capacitance of the defogger 90, 35
Is the stray capacitance of the cable. When the antenna conductor 3 and the defogger 90 are close to each other and capacitively coupled, the proximity capacitance due to this capacitive coupling is connected in parallel with the high-frequency choke coil 52.

The antenna conductor 3 is preferably used mainly for reception in the FM broadcast band, and the conductor length and the conductor shape are preferably set so as to obtain a suitable reception performance in the FM broadcast band. The antenna conductor 3 may be used for receiving a medium-wave broadcast band, a short-wave broadcast band, a long-wave broadcast band, a television VHF band, a television UHF band, a telephone band, and the like.

The defogger 90 is mainly used for receiving a long wave broadcast band. Furthermore, since the long-wave broadcast band and the medium-wave broadcast band have similar frequencies, the defogger 90 may be used for receiving the long-wave broadcast band and the medium-wave broadcast band. Note that the defogger 90 is a short wave broadcasting band, an FM broadcasting band, a television VHF band, a television UHF band.
It also has a receiving function for a telephone band, a telephone band, and the like, but is not used in the glass antenna device for an automobile shown in FIG.

In the present invention, two resonances occur to improve the sensitivity. Regarding series resonance, defogger 9
The impedance of 0 and the inductance of the series resonance coil 31 are included as resonance elements. Defogger 90
Is the impedance when the defogger 90 is viewed from the feeding point 91, and the impedance of the defogger 90 mainly consists of the stray capacitance. The stray capacitance 34 is usually 50 to 300 pF.

Further, since the antenna conductor 3 and the defogger 90 are electrically connected, the impedance of the antenna conductor 3 also affects the series resonance, and can be a resonance element of the series resonance. Further, in the series resonance, the stray capacitance of the wiring around the series resonance coil 31 and the stray capacitance 35 of the cable 7a connected between the glass antenna and the receiver 7 are set.
And so on, and can be a resonance element of series resonance. When the resonance circuit 6 is provided at or near the rear window glass plate 1, the length of the cable 7a is several meters since the receiver 7 is usually provided at the front of the vehicle. The capacitance value of the stray capacitance 35 is usually 50 to 300 pF.

A new circuit element may be provided inside the resonance circuit 6 to perform impedance matching between the antenna conductor 3 and the receiver. In order to improve the sensitivity of the long wave broadcast band, a coil having a series resonance of 10 μH to 1 mH is usually used. Within this range, 50 to 500 μH is more preferred, and 65 to 350 μH is even more preferred.

In the present invention, the sensitivity in the longwave broadcasting band is improved by causing parallel resonance. When the parallel resonance frequency is set to a frequency at which the sensitivity of the long-wave broadcasting band is improved, if the capacitance serving as the resonance element of the parallel resonance is mainly only the stray capacitance 34, the inductance of the choke coil 9 must be increased. Therefore, by adding the capacitor 32 for parallel resonance and making the capacitor 32 for parallel resonance a capacitor serving as a resonance element of parallel resonance, the inductance of the choke coil 9 can be made relatively small.

The inductance of the choke coil 9 is 0.
A range of 5 to 5.0 mH is preferred. Within this range, the parallel resonance frequency can be set to a frequency at which the sensitivity of the long-wave broadcast band is normally improved, and the choke coil 9 can be downsized. A more preferred range is from 1.0 to 3.0 mH, and a particularly preferred range is from 1.5 to 3.0 mH.

In FIG. 1, the parallel resonance is the main resonance element, which includes the inductance of the choke coil 9, the impedance of the defogger 90 and the capacitance of the capacitor 32 for parallel resonance. A capacitor of about 10 to 5000 pF can be generally used as the parallel resonance capacitor 32.

However, the stray capacitance 34 is usually 50 to 300
Considering that the capacitance is about pF, the preferable range of the capacitance value of the capacitor 32 for parallel resonance is 50 to 1200 pF.
It is. Within this range, the inductance of the choke coil 9 can be usually set to 5.0 mH or less, and the parallel resonance frequency can be set to a frequency at which the sensitivity of the long wave broadcasting band is usually improved. A more preferred range is 100 to 500 pF.

The resistor 48 is a resistor for adjusting the damping of the parallel resonance, and the preferable range of the resistance value of the resistor 48 is 200.
Ω to 25 kΩ. Within this range, the difference between the highest sensitivity and the lowest sensitivity in the longwave broadcasting band can be usually made 10 dB or less. The resistor 48 also has a function of adjusting the coupling between the antenna conductor 3 and the defogger 3, and is preferably provided. When the resistor 48 is provided, the sensitivity in the longwave broadcasting band is improved as compared with the case where the resistor 48 is not provided. In order to adjust the damping of the parallel resonance, a resistor 49 may be connected in parallel to the capacitor 32 for parallel resonance, or the resistors 20 and 21 may be connected in parallel to the choke coil 9.

Further, since the antenna conductor 3 and the defogger 90 are electrically connected, the impedance of the antenna conductor 3 also affects the parallel resonance, and can be a resonance element of the parallel resonance. The stray capacitance of the wiring around the antenna conductor 3, the stray capacitance of the wiring around the defogger 90, the stray capacitance of the wiring around the capacitor 32 for parallel resonance, and the like also affect the parallel resonance, and can be a resonance element of the parallel resonance. The stray capacitance of the cable 7a connected between the output of the resonance circuit 6 and the receiver 7 also affects the parallel resonance.

In FIG. 1, the resonance frequency of the series resonance and the resonance frequency of the parallel resonance are frequencies at which the sensitivity in the long-wave broadcasting band is improved. That is, the parallel resonance frequency is 100 to 1
80 kHz is preferable, and 120 to 150 kHz is more preferable. The series resonance frequency is 1300-2100k
Hz is preferable, and 1500 to 1800 kHz is more preferable.

In FIG. 1, a high-frequency choke coil 52, which is an inductance element, separates the antenna conductor 3 and the defogger 90 from each other in a high frequency band in a normal FM broadcast band, and does not change the effective length of the conductor of the antenna conductor 3. It has the function of improving the sensitivity in the broadcasting band.

When the high-frequency choke coil 52 is not provided and the high-frequency choke coil 52 is short-circuited, the self-resonant frequency of the choke coil 9 is low in the FM broadcasting band, and the capacitance usually appears. The high frequency choke coil 52 is provided to prevent the reception signal of the FM broadcast band excited at 3 from leaking to the vehicle body ground. In other words, the high-frequency choke coil 52
Has a function as a filter circuit that passes the frequency of the long wave broadcast band and cuts off or attenuates the frequency of the FM broadcast band. In addition, the high frequency choke coil 52 also passes the frequency of the medium wave broadcast band. In addition, as the filter circuit 8,
Since the circuit is simple and inexpensive, it is preferable to use the high-frequency choke coil 52 shown in FIG. But,
The present invention is not limited to this, and the filter circuit 8 may have another circuit configuration. The connection of the filter circuit 8 is not limited to the configuration of FIG. 1, and it is sufficient that the filter circuit 8 is electrically connected between the antenna conductor 3 and the defogger 90 via at least one of a wiring and a circuit element.

When the long-wave broadcasting band and the FM broadcasting band are included in the receiving broadcasting band, the high-frequency choke coil 52
Those having an inductance value in the range of 0.1 to 100 μH are preferred. 0.1 to 10 when the inductance value of the high-frequency choke coil 52 is in the range of 0.1 to 100 μH.
The sensitivity of the FM broadcast band is improved as compared with the case outside the range of 0 μH. From the viewpoint of improving the sensitivity of the FM broadcast band, the high-frequency choke coil 52 preferably has an inductance value in the range of 0.3 to 20 μH, and more preferably 0.8 to 4.8 μH.
Those having an inductance value in the range described above are particularly preferable.

The self-resonant frequency f _R of the high-frequency choke coil 52, due to the increased sensitivity of the FM broadcast band, and the highest frequency f _H of the FM broadcast band, between the lowest frequency f _L of the FM broadcast band, f _H / satisfy is preferably of 15 ≦ f _R ≦ 3f _L, more preferably _{f H / 9 ≦ f R ≦} 2f L, f H / 3.
6 ≦ f _R ≦ 1.85f _L is particularly preferred.

In FIG. 1, it is preferable that the antenna conductor 3 and the defogger 90 are not capacitively coupled as much as possible. In the case of capacitive coupling, the reception signal of the FM broadcast band excited by the antenna conductor 3 easily leaks to the vehicle body ground via the defogger 90 and the choke coil 9. In order to minimize the capacitive coupling between the antenna conductor 3 and the defogger 90, it is preferable that the shortest distance between the antenna conductor 3 and the defogger 90 be 10 mm or more. When the shortest interval is 10 mm or more, the sensitivity of the FM broadcast band is improved as compared with the case where the shortest interval is less than 10 mm. More preferably, the shortest interval is 20 mm or more. The shortest interval is 20mm
In the above case, the sensitivity of the FM broadcast band is improved as compared with the case where the distance is less than 20 mm.

The above-described antenna conductor 3 and defogger 90
Is normally applied when the length of the substantially parallel portion between the antenna conductor 3 and the defogger 90 is 100 mm or more.

When the shortest distance between the antenna conductor 3 and the defogger 90 must be less than 10 mm because the vertical dimension of the rear window glass plate 1 is short, as shown in FIG. It is preferable that a high-frequency choke coil is inserted and connected between the bus bar 5b and the vehicle body ground. This is because the reception signal of the FM broadcast band excited by the antenna conductor 3 is cut off by the high-frequency choke coil so as not to leak to the vehicle body ground.

FIG. 2 shows a development of the automotive glass antenna apparatus of FIG. 1 for diversity reception. In FIG. 2, 53 is a capacitor, 60 is a high-frequency choke coil, t ₁ is the first input of the receiver 7, t ₂
Is the second input of the receiver 7. The receiver 7 selects the stronger one of the received signals of the FM broadcast band between the first input t ₁ and the second input t ₂ .

The capacitor 53 is provided as needed.
It has a function of blocking or attenuating a received signal in the longwave broadcasting band. The capacitance value of the capacitor 53 is preferably in the range of 10 to 500 pF, and more preferably in the range of 30 to 150 pF.
When the capacitance value of the capacitor 53 is 10 pF or more, 10
F at the second input t ₂ , compared to less than pF
The sensitivity of the M broadcast band is improved. When the capacitance value of the capacitor 53 is 500 pF or less, the sensitivity of the long-wave broadcast band at the _first input t1 is improved as compared with the case where the capacitance value exceeds 500 pF.

The reception signal of the FM broadcast band leaks to the vehicle body ground via the capacitor 32 for parallel resonance, and the sensitivity of the FM broadcast band decreases. To prevent this, a high-frequency choke coil 60 may be connected in series to the capacitor 32 for parallel resonance. Usually, about 0.1 to 100 μH is used for the high frequency choke coil 60.

In the automobile glass antenna device shown in FIG.
It is preferable to connect the high-frequency choke coils 12 a and 12 b between the bus bar and the choke coil 9. The connection in this manner is such that the apparatus of FIG. 1 does not use the received signal of the FM broadcast band excited by the defogger 90, but the apparatus of FIG.
To use the received signals of the excited FM broadcast band at a second input t _2, the high-frequency choke coils 12a, leakage of the vehicle body ground of the received signal of the excited FM broadcast band in the defogger 90 at 12b prevent To do that.

In FIG. 2, the second input t ₂ of the receiver 7 is extracted from the inside of the resonance circuit 6 (the defogger 90 side end of the capacitor 53 is connected to the inside of the resonance circuit 6). However, the location from which the second input t ₂ is extracted is not limited to the inside of the resonance circuit 6, and may be extracted from any location of the defogger 90. Further, an antenna conductor different from the antenna conductor 3 is provided in a blank portion below the defogger 90 to provide a first antenna.
It may perform diversity reception between the input t ₁ and another antenna conductor.

In the present invention, two resonances are generated because only one resonance cannot cover a wide reception frequency band. Therefore, in the present invention, the long wave broadcasting band is shared by the two resonances, and the sensitivity is flattened. When the medium-wave broadcast band is also received, the frequency band from the long-wave broadcast band to the medium-wave broadcast band is shared by the two resonances, and the sensitivity is flattened. Sensitivity flattening refers to reducing the difference between the highest sensitivity and the lowest sensitivity within the longwave broadcasting band.

FIG. 4 is a circuit diagram of a modification of the resonance circuit 6. In FIG. 4, 41, 44, and 50 are DC cut capacitors, 43 is a DC cut or coupling capacitor, 45, 46, 48, and 49 are damping resistors.
4 is a bypass capacitor, 55 is a resistor for adjusting the coupling, 5
Reference numeral 6 denotes a coupling adjusting capacitor.

In the resonance circuit of FIG. 4, the reception signal of the defogger 90 is transmitted to the receiver via the resistor 47, the high-frequency choke coil 52, and the capacitor 43. However, when the antenna conductor 3 and the defogger 90 are capacitively coupled, the reception signal of the defogger 90 is transmitted to the receiver side even through the proximity capacitance.

The capacitors 43 and 56 are for adjusting the coupling between the antenna conductor 3 and the defogger 90.
Provided as needed. Further, resistors 45, 46, 48, 49, and 55 are provided as necessary to adjust the flatness of the sensitivity. In addition, a capacitor or the like for resonance adjustment may be provided.

Capacitors 41, 44, 50, 54, 56
Is provided as needed, and usually 100 pF to 50 μF is used. Usually, 5 to 500 pF is used for the capacitor 43. Normally 50 for resistors 45, 46, 49 and 55
Ω to 100 kΩ is used.

Further, a lead wire for supplying a DC current from the DC power supply 10 to the defogger 90 picks up vehicle noise such as engine noise and causes a deterioration in the S / N ratio. The resistor 47 is provided as needed, and has a function of preventing the deterioration of the S / N ratio. In particular, it has a function of preventing the deterioration of the S / N ratio in the low band of the long wave broadcasting band. That is, the resistor 47 has a function of reducing vehicle noise such as engine noise.

The resistance value of the resistor 47 is preferably 10 Ω to 1 kΩ, and more preferably 50 to 500 Ω. When the resistance value of the resistor 47 is set to 10Ω to 1 kΩ, the S / N ratio of the long wave broadcast band is usually improved as compared with the case where the resistance value is out of the range of 10Ω to 1 kΩ. When the resistance value of the resistor 47 is set to 50 to 500Ω, the S / N ratio of the long wave broadcast band is usually improved as compared with the case where the resistance is outside the range of 50 to 500Ω.

As described above, in FIG. 4, the capacitors 41, 43, 44, 50, 51, 54, 56 and the resistor 4
5, 46, 47, 48, 49, and 55 are provided as necessary and can be omitted. Here, the omission of the capacitor 56 and the omission of the resistors 45, 46, 49, and 55 are open, and the omission of the capacitors 41, 43, 50, 51, 54, and the omission of the resistors 47 and 48 are short-circuited. It is to be.

FIG. 5 is a block diagram of an embodiment of a glass antenna device for a vehicle different from that of FIG. The vehicle glass antenna device of FIG. 5 uses a resonance circuit 6 different from that of FIG. 1, and a capacitor 32 for parallel resonance is not interposed between the receiver 7 and the vehicle body ground without a series resonance coil. In addition, they are electrically connected via wiring and / or circuit elements.

In FIG. 5, A, B, C, D, and E indicate locations on the line, where A is one end of the capacitor 51 opposite to the defogger 90, and B is the feed point 4 and the receiver 7
C is one end of the parallel resonance capacitor 32 on the side opposite to the vehicle body ground, and D is a resistor 47.
The point E of the line between the high-frequency choke coil 52 and the high-frequency choke coil 52 is the coil 3 for series resonance with the high-frequency choke coil 52.
This is the location of the track between the two.

In FIG. 1, the point C is electrically connected to the feeding point 91 via the wiring and the capacitor 51. In FIG. 5, the point C is electrically connected to the point B via the wiring. I have. In other words, in FIG. 5, the parallel resonance capacitor 32 is electrically connected between the antenna conductor 3 and the vehicle body ground via the capacitor 50, the resistor 48, the high-frequency choke coil 60, and the wiring. The connection of the capacitor 32 for parallel resonance is not limited to the configuration of FIG.
It is sufficient that the parallel resonance capacitor 32 is electrically connected between the antenna conductor 3 and the vehicle body ground via at least one of the wiring and the circuit element. Further, it can be used even if the location C is electrically connected to the location D or the location E via at least one of a wiring and a circuit element.

FIG. 6 is a configuration diagram of an embodiment in which the connection order of the series resonance coil 31 and the high frequency choke coil 52 in FIG. 5 is changed. When viewed from the output terminal 6c side, the high-frequency choke coil 5 is located between the output terminal 6c and the input terminal 6a.
2. A series resonance coil 31 and a resistor 47 are connected in series in this order. In addition, location C is connected to location E. Therefore, in FIG. 6, the line C between the input terminal 6b and the output terminal 6c, and the point C is the high-frequency choke coil 5
2 is connected to a line closer to the defogger 90 than the defogger 90. Therefore, the reception signal in the high frequency band at the output terminal 6c is cut off by the high frequency choke coil 52 and is unlikely to leak to the vehicle body ground. No need.

5 and 6, the resistance of the resistor 47 is very small (for example, several tens of ohms).
In the following case, the operation of the series resonance and the operation of the parallel resonance are very similar to those of the resonance circuit 6 in FIG.
The conditions of the above-described FIG. 1 such as the distance between the antenna conductor 3 and the defogger 90, circuit constants, and resonance conditions can all be applied to the resonance circuit 6 of FIGS.

However, comparing the resonance circuit 6 in FIG. 1 with the resonance circuit 6 in FIGS. 5 and 6, in the resonance circuit 6 in FIGS.
The capacitor 32 and the stray capacitance 35 are connected in parallel so that the capacitance of the capacitor 32 becomes apparently large, and is unlikely to affect the parallel resonance. Therefore, when the choke coil 9 having the same specification is used, the sensitivity of the long-wave broadcast band of the glass antenna device for an automobile of FIG. Because of its large size, the resonance circuit 6 of FIG. 1 is more preferable than the resonance circuits 6 of FIGS.

In FIG. 2, a choke coil 9 is provided between the bus bars 5a and 5b and the DC power supply 10 for the defogger 90.
By inserting the high-frequency choke coils 12a and 12b and increasing the impedance of the choke coil 9 and the high-frequency choke coils 12a and 12b in the broadcast band, a DC current flows from the DC power supply 10 to the defogger 90, but a current in the broadcast band. Is trying to shut off.

In this way, the defogger 9 is formed by the choke coil 9 and the high-frequency choke coils 12a and 12b.
The heater wire 2 and the bus bars 5a and 5b can be insulated from the vehicle body ground at a high frequency, and the reception current of the broadcasting band induced by the defogger 90 can be prevented from flowing to the vehicle body ground. Can be sent to the machine. The choke coil 9 is usually used at a pressure of about 0.1 to 10 mH.

The high-frequency choke coils 12a and 12b and the high-frequency choke coil 60 have high impedance in a high frequency band such as the FM broadcast band of the broadcast band, and usually use a solenoid or a magnetic core.
They have an inductive inductance in and around high frequency bands, such as the FM broadcast band.

In a high frequency band such as an FM broadcasting band, the self-resonant frequency of the choke coil 9 is low, and the impedance of the choke coil 9 usually has a low impedance due to the appearance of capacitance.
a and 12b act on behalf of this. High frequency choke coil 1
For 2a and 12b, about 0.1 to 100 μH is used.

In a high frequency band such as an FM broadcasting band, when the impedance of the choke coil 9 does not appear capacitive and the choke coil 9 has a high impedance as a result, the high-frequency choke coils 12a and 12b
Is unnecessary. Further, if there is a coil that satisfies both functions of the choke coil 9 and the high-frequency choke coils 12a and 12b, only such a coil may be used.

The defogger 90 shown in FIGS. 1 and 2 has a so-called substantially U-shape.
0 is not limited to this, and a so-called substantially U-shaped defogger 90 as shown in FIG. 10 can be used in the present invention. The antenna conductor 3 is connected to the defogger 90 of the window glass plate 1.
It may be provided anywhere in the upper, lower, left, or right margin, and is not limited to the position shown in FIG. The number of antenna conductors provided on the window glass plate 1 is not particularly limited.

In the present invention, the number of antenna conductors provided on a vehicle other than the antenna conductor 3 is not limited.
Further, diversity reception may be performed between the glass antenna device of the present invention and another antenna device such as a pole antenna or another glass antenna device.

[0060]

EXAMPLE 1 Example 1 Using a Rear Window Glass Plate of a Car
The glass antenna device shown in FIG. 1 was manufactured. Resistance 20,
21 and 49 were not provided, and the resistors 20, 21 and 49 were opened. Table 1 shows each circuit constant.

The conductor length and the shape of the antenna conductor 3 were adjusted so that the FM broadcasting band could be received. The distance between the lower portion of the antenna conductor 3 and the uppermost line of the heater wire 2 was increased to 21 mm. In this case, the antenna conductor 3 and the defogger 90
Almost no capacitive coupling.

The frequency-sensitivity characteristics near the long-wave broadcasting band of the glass antenna device of Example 1 are shown by the thick solid line in FIG. Also,
The frequency-sensitivity characteristics in the vicinity of the long wave broadcast band and the medium wave broadcast band of the glass antenna device of Example 1 are shown by the thick solid line in FIG. The sensitivity of the 870 mm long pole antenna is about -26 dB in the long wave broadcasting band, and -24 dB in the medium wave broadcasting band.
It was about dB.

[Examples 2 and 3] A glass antenna device having exactly the same specifications as in Example 1 was manufactured except that the value of the resistor 48 was changed to 220Ω (Example 2) and 22 kΩ (Example 3). The frequency-sensitivity characteristics are shown by thin solid lines (Example 2) and broken lines (Example 3) in FIGS.

[0064]

[Table 1]

Example 4 A glass antenna device shown in FIG. 5 was manufactured using a rear window glass plate of an automobile. Resistance 2
0, 21, and 49 were not provided, and the locations of the resistors 20, 21, and 49 were left open. Table 2 shows each circuit constant. The specifications other than the circuit constants shown in Table 2 were exactly the same as in Example 1. FIG. 9 shows frequency-sensitivity characteristics near the long-wave broadcast band and the medium-wave broadcast band.

[0066]

[Table 2]

[0067]

According to the present invention, a series resonance including the impedance of the antenna conductor and the inductance of the series resonance coil as resonance elements is generated, and the parallel resonance including the impedance of the defogger and the parallel resonance capacitor as resonance elements. The two resonances are used, so that the sensitivity in the long wave broadcasting band is excellent, the size of the choke coil 9 can be reduced, and the cost can be reduced.

When a filter circuit for cutting off or attenuating a received signal in the FM broadcast band is electrically connected between the antenna conductor and the defogger, the received signal in the FM broadcast band excited by the antenna conductor is not transmitted. The leakage to the vehicle body ground is small, and the sensitivity of the FM broadcast band is rarely reduced. Furthermore, when receiving a long-wave broadcast band, both the antenna conductor and the defogger can be used, so that the sensitivity of the long-wave broadcast band is excellent. When receiving the FM broadcast band, the effective length of only the antenna conductor can be used, so that the FM broadcast can be used. Excellent band sensitivity.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of one embodiment of a glass antenna device for an automobile of the present invention.

FIG. 2 is a configuration diagram of another embodiment of the glass antenna device for a vehicle according to the present invention.

FIG. 3 is an equivalent circuit diagram for explaining the operation of the antenna conductor 3, the defogger 90 and the resonance circuit 6 in the device of FIG.

FIG. 4 is a circuit diagram of a modification of the resonance circuit 6.

FIG. 5 is a configuration diagram of an embodiment of a glass antenna device for a vehicle different from that of FIG. 1;

FIG. 6 is a configuration diagram of an embodiment in which the connection order of the series resonance coil 31 and the high-frequency choke coil 52 in FIG. 5 is changed.

FIG. 7 is a diagram showing frequency-sensitivity characteristics in the vicinity of a long-wave broadcast band in Examples 1, 2, and 3;

FIG. 8 is a frequency-sensitivity characteristic diagram in the vicinity of a long-wave broadcast band and a medium-wave broadcast band in Examples 1, 2, and 3.

FIG. 9 is a diagram showing frequency-sensitivity characteristics in the vicinity of a long-wave broadcast band and a medium-wave broadcast band in Example 4;

FIG. 10 is a configuration diagram of a conventional glass antenna device for an automobile.

[Explanation of symbols]

 1: Rear window glass plate of automobile 2: Heater wire 3: Antenna conductor 3b: Defogger 4: Feeding point 5a, 5b: Bus bar 6: Resonance circuit 6a, 6b: Input terminal of resonance circuit 6 6c: Output terminal of resonance circuit 6 7: Receiver 7a: Cable 8: Filter circuit 9: Choke coil 10: DC power supply 20, 21: Resistance for damping 31: Coil for series resonance 32: Capacitor for parallel resonance 33: Stray capacitance of antenna conductor 3 34 : Stray capacitance of defogger 90 35: Stray capacitance of cable 7a 41: DC cut capacitor 43: DC cut or coupling capacitor 45: Damping resistor 48, 49: Damping resistor 47: Resistor 52: High frequency choke Coil 90: Defogger E1: Voltage power supply for antenna conductor 3 E2: Voltage power supply for defogger 90

Claims (7)

[Claims] An electric heating type defogger having a heater wire and a bus bar for supplying power to the heater wire, and an antenna conductor are provided on a rear window glass plate of the automobile, and are provided between the bus bar and a DC power supply. A glass antenna device for an automobile, in which a choke coil is connected to at least one of between a bus bar and a vehicle body ground, comprising a series resonance coil and a parallel resonance capacitor, and a defogger impedance and a series resonance A series resonance that includes the inductance of the coil as a resonance element is generated, and a parallel resonance that includes the impedance of the defogger and the inductance of the choke coil as a resonance element is generated, and at least a reception signal in a long-wave broadcasting band is received from the defogger. And at least the received signal of the FM broadcast band is transmitted to the antenna conductor. The resonance frequency of the series resonance and the resonance frequency of the parallel resonance that are sent to the receiver are the frequencies at which the sensitivity of the long-wave broadcasting band is improved.A capacitor for parallel resonance is electrically connected between the defogger and the vehicle body ground. A glass antenna device for a vehicle, wherein the glass antenna device is connected to a vehicle. 2. The automotive glass antenna device according to claim 1, wherein the inductance of the choke coil, the impedance of the defogger, and the capacitance of the capacitor for parallel resonance are main resonance elements of parallel resonance. 3. A capacitor for parallel resonance is electrically connected between a receiver and a vehicle body ground via a wiring and / or a circuit element without passing through a series resonance coil. 3. The glass antenna device for an automobile according to 1 or 2. 4. An electric heating type defogger having a heater wire and a bus bar for supplying power to the heater wire, and an antenna conductor are provided on a rear window glass plate of the automobile, between the bus bar and the DC power source, and A choke coil is connected to at least one of the bus bar and the vehicle body ground, and the received signal of the antenna conductor is sent to the receiver. Are electrically connected via wiring and / or circuit elements, and a capacitor for parallel resonance is wired between at least one of between the defogger and the vehicle body ground and between the antenna conductor and the vehicle body ground. And / or electrically connected via a circuit element. 5. A filter circuit according to claim 1, wherein a filter circuit for blocking or attenuating a received signal in the FM broadcast band is electrically connected between the antenna conductor and the defogger via a wiring and / or a circuit element. A glass antenna device for an automobile according to the present invention. 6. A capacitor for parallel resonance having a capacitance value of 50 to 50.
The glass antenna device for an automobile according to any one of claims 1 to 5, which is 1200 pF. 7. The vehicle according to claim 1, wherein a series connection circuit of a resistor having a resistance value of 200Ω to 25 kΩ and a capacitor for parallel resonance is inserted and connected between the defogger and the vehicle body ground. Glass antenna device.