JPH07240614A - Glass pane antenna for automobile - Google Patents

Abstract

PURPOSE:To provide a glass pane antenna for an automobile capable of receiving a wide band signals from an FM radio broadcast wave to a TV broadcast wave UHF band by utilizing the colored opaque layer of an automobile peripheral part and effectively utilizing space. CONSTITUTION:First antennas 31 and 32 provided at least with a horizontal wire, a vertical wire, or the horizontal wire and the vertical wire are provided within the range of the lower layer of a colored opaque band formed in the peripheral part of window glass 1 for the automobile, and second antennas 61 and 62 for performing capacitive coupling with at least a part of the first antennas 31 and 32 are provided in the upper layer of the colored opaque band. The external conductor of a coaxial cable is connected to the first antennas 31 and 32 and an internal conductor is connected to the second antennas 61 and 62 or the internal conductor is connected to the first antennas 31 and 32 and the external conductor is connected to the second antennas 61 and 62.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass antenna provided on a rear window glass or a front window glass of an automobile, and more particularly to a glass antenna suitable for receiving FM radio broadcast waves and TV broadcast waves.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a glass antenna for a vehicle for receiving TV broadcast waves other than radio broadcast waves such as AM and FM, and a vertical antenna is provided on the front window glass. What is provided (JP-A-61-2370)
No. 2), etc., but it is not practically used because it may obstruct the driver's field of view. Even if it is provided, the area occupied by the antenna must be small, and it is difficult to obtain sufficient reception gain. Is.

In practice, a glass antenna provided on a rear window glass together with a heating wire for anti-fog occupies the mainstream, and various proposals such as JP-A-61-1121603 and JP-A-2-218202 have been proposed. However, since the plurality of heating filaments occupy most of the area of the rear window glass, the area occupied by the antenna becomes small, and it is difficult to obtain a sufficient reception gain.

[0004] Therefore, a device which effectively utilizes the space by providing an antenna on the upper and lower two layers through an insulating layer is disclosed in Japanese Utility Model Publication No. Sho 52-.
No. 147151 and Japanese Patent Laid-Open No. 3-145203 have been proposed, but in both cases, the upper and lower antennas are arranged so as not to be in parallel with each other so that the upper and lower antennas do not interfere with each other. The front surface of the inner glass plate and the back surface of the inner glass plate (the mating surface side)
For example, when it is provided above and below via the insulating glass sheet, it is necessary to cut out the glass sheet to the feeding point on the inside glass sheet surface in order to pull it out from the antenna on the inside glass sheet back surface. In the case where the upper and lower antennas are provided on the surface, it is necessary to newly provide the insulating layers at the intersecting positions, and it is inevitable that the number of processes increases and the cost becomes high.

The present invention has been made in view of the above circumstances, and positively interferes by arranging the two-layer structure antennas so that at least some of them are close to each other and parallel to each other. In addition, it is an object of the present invention to provide a glass antenna in which an insulating layer for insulating the upper and lower antennas also serves as a black colored opaque layer commonly called a black frame.

[0006]

The present invention has at least horizontal stripes, vertical stripes, or horizontal and vertical stripes within the lower layer of the colored opaque band formed on the peripheral portion of the window glass for automobiles. A first antenna is provided, and a second antenna that capacitively couples with at least a part of the first antenna is provided on the upper layer of the colored opaque band, and an internal conductor of a coaxial cable is provided to the second antenna. The outer conductor of the coaxial cable is connected to the first antenna, or the inner conductor of the coaxial cable is connected to the first antenna and the outer conductor of the coaxial cable is connected to the second antenna. The first antenna is entirely provided under the colored opaque band, or
Alternatively, a part of the antenna is provided so as to protrude from the colored opaque band, and diversity reception is further performed by an antenna different from the antenna of the present invention, or a plurality of antennas of the present invention are provided and diversity reception is performed by each antenna. It is more preferable to provide a plurality of antennas and add another antenna for diversity reception.

[0007]

In the conventional two-layer structure antenna, it is considered that it is better not to interfere with each other because the reception gain is lowered when capacitively coupled. This is for capacitively coupling to improve the reception gain. Further, if it is close to the glass edge, the reception gain is lowered due to the influence of the body (metal) of the automobile. Therefore, generally, it is separated from the glass edge by, for example, about 50 mm. In the present invention, the electrostatic capacitance formed by the upper and lower antennas is formed between the filament of the antenna and the metal body even if the colored opaque layers are provided in the upper and lower layers of the glass peripheral portion in the present invention. Since it is much larger than the electrostatic capacitance, it can be ignored, and the reception gain is hardly reduced. Compared with the case of only the upper layer antenna, the FM radio broadcasting wave to the TV broadcasting wave are wider. It can be received with high gain over a frequency range.

In this case, the distance between the upper and lower antennas forming the electrostatic capacitance is determined by the thickness of the colored opaque layer (generally 10 μm).
.About.20 .mu.m) or more and 10 mm or less, preferably 5 mm or less, and the length of the filaments in which the upper and lower two-layer antennas are close and parallel to each other is long, the reception gain is improved for radio waves of low frequency. Since the frequency of the radio wave to be improved becomes higher as it becomes shorter, when improving the reception gain for the FM radio broadcast wave, the reception gain for the radio wave such as the TV broadcast wave UHF band with a frequency higher than 500 mm or higher is improved. If you want to make it 50 mm or more 300
The range of mm is better.

The first antenna may be connected to the outer conductor of the coaxial cable and the second antenna may be connected to the inner conductor, or conversely, the first antenna may be connected to the inner conductor of the coaxial cable and the second antenna may be connected to the outer conductor. By connecting to the conductor,
This is used as a non-grounded antenna. In a grounded antenna, the external conductor of the coaxial cable must be grounded to the metal body (body) near the antenna, and there is a risk that the grounding resistance will reduce the reception gain. However, since the present invention is a non-grounded type, there is no need for grounding,
It is possible to avoid a decrease in reception gain due to ground resistance.
Furthermore, by making it an ungrounded type, since it acts as an impedance matching with the unbalanced power feeding system (coaxial cable),
It is possible to reduce the transmission loss and improve the reception gain.

Since the colored opaque layer also serves as the insulating layer, it is possible to effectively use the blank portion without newly providing an insulating layer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. 1 to 3 are all front views in which the glass antenna of the present invention is provided on a rear window glass for an automobile.
Shows Example 1 and Example 2, FIG. 2 shows Example 3, and FIG. 3 shows Example 4 and Example 5.

Embodiment 1 and Embodiment 2 As shown in FIG. 1, the antenna of Embodiment 1 is placed in the upper margin of the anti-fogging heating wire, and the antenna of Embodiment 2 is placed in the lower margin of the anti-fog heating wire. An example will be given for the case where two are provided.

On the inside of the sheet glass 1 constituting the rear window glass for automobiles, first, the length of the uppermost horizontal filament is 110.
0mm, vertical wire length on the left side is 300mm,
The length of the two horizontal filaments connected to the vertical filaments is 400m
m, the length of the vertical filament that closes the tip of this horizontal filament is 50
The first antenna 3 ₁ (shown by a dotted line) in Example 1 having a length of 300 mm and the first antenna 3 ₂ (shown by a dotted line) in Example 2 in which the horizontal filament has a length of 300 mm are respectively supplied to the first feeding points 4 respectively. _1, together with 4 _2, screen printing of a conductive paste and dried, after which the colored opaque layer 5 wide black indicating the contour by the dotted line on the window glass periphery of screen printing a ceramic paste except feed portion And after drying, the anti-fogging heating filaments 2, 2, ..., 2
With both ends a length of conventionally well as a second antenna ₆₁ in the antenna Example 1 known, (horizontal strip of 50mm is connected to the horizontal strip of the top) horizontal strip of 250mm length There second feeding point _71, respectively as the second antenna 6 ₂ in example 2 connected by vertical strip of 60 mm, screen printing with a conductive paste with a feeding point 7 _2.

Next, when this plate glass is bent in a heating furnace, it is fired at the same time. When the glass antenna for a vehicle thus obtained is mounted as a rear window glass for an automobile, the size of each part is A ₁ = 1200 mm, A
_{2 = 1370mm, B = 850mm,} a 1 = a 2 = 50
0 mm, b ₁ = 340 mm, b ₂ = 160 mm, c ₁ =
500 mm, c ₂ = 540 mm, d = 50 mm, e = 2
0 mm, f = 30 mm, and the distance between the first antenna and the second antenna forming the capacitive coupling is set to substantially overlap with each other in a plane.
The close parallel length is 1000 mm in Example 1 and 2 in Example 2.
76MHz ~ 90MHz depending on what is 50mm
FM radio broadcast wave, TV broadcast wave in 1 to 3 channels VHF band low channel (hereinafter, TV broadcast wave VHF
-Abbreviated as L band) TV in 4 to 12 channels
Broadcast wave VHF band high channel (hereinafter, TV broadcast wave VH
The F-H band is abbreviated.) The reception gain of the TV broadcast wave UHF band of 470 MHz to 770 MHz is individually measured, and the gain difference when the reception gain of the standard dipole antenna is set to 0 dB (hereinafter referred to as the dipole ratio). Abbreviated), the antenna of the first embodiment has an average value of −20.
1 dB, -18.1 dB, -19.7 dB, -17.8
dB, and the respective reception gains in the case where there is no first antenna indicated by the dotted line are -19.9 dB and -17.5 d on average.
B, -23.5 dB, -18.9 dB, so FM
Radio broadcast wave, TV broadcast wave VHF band-L band equivalent, TV
It can be seen that it is higher in the broadcast wave VHF-H band and the TV broadcast wave UHF band, and in particular, the gain of the TV broadcast wave VHF-H band is greatly improved.

The FM radio broadcast wave and the TV broadcast wave VHF-L are generated by the antenna of the second embodiment shown by the first antenna 3 ₂ , the second antenna 6 ₂ , and the feeding points 4 ₂ and 7 _2.
Band, TV broadcast wave VHF-H band, TV broadcast wave UHF band, respectively, the reception gain is measured individually, and when expressed as a dipole ratio, the average values are −22.7 dB and −21.9 d, respectively.
B, -18.2 dB, -16.2 dB, and the respective reception gains in the case where there is no dotted first antenna is -24.7 dB, -24.1 dB, -20.4 dB, on average.
Since it is -19.1 dB, it is higher in all bands, and it can be seen that the reception gain is greatly improved particularly in the TV broadcast wave VHF-H band and the TV broadcast wave UHF band.

Further, the reception gain of a good glass antenna for a vehicle, which has been put to practical use in the past, has an FM radio broadcast wave, T
V broadcast wave VHF-L band, TV broadcast wave VHF-H band, TV
Approximately -20d on average for each broadcast wave UHF band
B, about -20 dB, about -20 dB, and about -18 dB, the antennas of Example 1 and Example 2 are almost the same as or above, and it can be seen that they are good antennas.

The glass antenna having the structure shown in FIG. 1 has a whip antenna (not shown) to receive AM radio broadcast waves by the whip antenna,
For the M radio broadcast wave to TV broadcast wave UHF band, diversity reception is performed by the whip antenna, the antenna of the first embodiment of the present invention, and the antenna of the second embodiment.
Of course, diversity reception may be performed in combination with an antenna (not shown).

Example 3 As shown in FIG. 2, the first antenna 3 ₃ shown by a dotted line is
Example 1 except that only a horizontal filament having a length of 550 mm was used.
It has the same configuration and dimensions as the above, and by the glass antenna for a vehicle thus obtained, FM radio broadcast wave, TV broadcast wave VHF-L band, TV broadcast wave VHF-H
Band and TV broadcast wave UHF band reception gains are measured individually and shown in dipole ratios.
1.5 dB, -19.2 dB, -20.5 dB, -1
The value is 7.3 dB, which is close to the reception gain of the antenna of the first embodiment.

Example 4, Example 5 As shown in FIG. 3, the antenna of Example 4 was placed in the upper margin of the anti-fogging heating wire, and the antenna of Example 5 was placed in the side margin of the anti-fogging heating wire. The case where two antennas are provided will be exemplified.

Example 4 is a horizontal glass strip having a length of 1000 mm on the inner side of the glass sheet 1 having the same dimensions as in Example 1.
The first antenna 3 ₄ and the first antenna 3 ₅ a first feeding point 4 of Example 5 has a length consisting of vertical strip of 250mm of
_5, together with the second feed point 7 _5, screen printing with a conductive paste and dried, colored opaque layer subsequent black 5
Is screen-printed on the peripheral edge of the plate glass with a ceramic paste except for the first feeding point 4 ₅ and the second feeding point 7 ₅ , and is dried, and then the anti-fogging heating wire 2,
In addition to 2, 2, 2, the second antenna 6 ₄ of Example 4 and the second feeding point 7 ₄ are provided in the upper margin of the heating wire.
The second antenna 6 ₅ and the second feeding point 7 ₅ of Example 5, which are vertical filaments having a length of 350 mm, are screen-printed and fired with a conductive paste on the side margins of the heating filament.

When the glass antenna for a vehicle thus obtained is mounted as a rear window glass for an automobile,
The size of each part is g = 500 mm, h = 100 mm, i = 5
FM radio broadcast wave, TV broadcast wave VHF-L band, TV broadcast wave VH depending on what is set to 00 mm, j = 500 mm
When the reception gains of the F-H band and the TV broadcast wave UHF band are individually measured and shown by the dipole ratio, the antennas of the fourth embodiment have average values of -20.1 dB and -19.3 d, respectively.
B, -18.9 dB, -18.5 dB, and the antennas of Example 5 have average values of -25.2 dB and -20.6 d, respectively.
B, -17.8 dB, -15.1 dB, and in the case where there is no first antenna indicated by the dotted line, the average values are -21.2 dB, -21.0 dB, -19.
4 dB, −23.3 dB, and average values of −27.2 dB, −22.9 dB, and −17.9 dB for Example 5 respectively.
Since B and -19.2 dB, the antenna of the example 4 is superior in all bands, especially the TV broadcast wave UHF band is greatly improved, and the antenna of example 5 is also superior in all bands, especially the TV broadcast wave UHF. It can be seen that the belt has greatly improved.

The glass antenna having the configuration shown in FIG. 3 has a whip antenna (not shown) to receive AM radio broadcast waves by the whip antenna,
For the M radio broadcast wave to TV broadcast wave UHF band, diversity reception is performed by the whip antenna and the antenna of the present embodiment, but diversity reception may be performed in combination with other antennas not shown.

Other Embodiments The preferred embodiments have been described above, but the present invention is not limited to these, and various applications are possible.

Regarding the antenna pattern, various antennas capable of receiving FM radio broadcast waves and TV broadcast waves can be adopted as the second antenna, and the first antenna is designed to be capacitively coupled to the filament closest to the glass edge. It is possible to adopt a wire having a different line.

Although the power feeding is not described in the embodiment, the inner conductor of the coaxial cable is connected to the second feeding point,
The outer conductor is connected to the first feeding point, and this connection is preferable, but the inner conductor of the coaxial cable may be connected to the first feeding point and the outer conductor may be connected to the second feeding point.

Although the antenna of the present invention can be used alone, the antenna of the present invention can be used for diversity reception, or the antenna of the present invention can be provided for diversity reception. It is more preferable to provide a plurality of antennas and add another antenna for diversity reception.

In this case, of course, diversity reception may be performed by adding another glass antenna provided on the front or side window glass or a pole antenna such as a whip antenna.

Further, the antenna of the present invention may be provided not only on the rear window glass but also above and below the colored opaque band of the front window glass, and further above and below the colored opaque band of the side rear quarter. .

[0029]

Since the glass antenna of the present invention forms an antenna having an upper and lower two-layer structure, it is possible to effectively use the space. By adding the first antenna to the lower layer, the glass antenna of the upper layer can be used. Compared to the case of using only the antenna, the reception gain of the FM radio broadcast wave or TV broadcast wave can be improved without lowering the reception gain of the second antenna. As a result, there is no need for grounding, and it is possible to avoid a reduction in reception gain due to grounding resistance. Since it acts as an impedance match with the unbalanced power feeding system (coaxial cable), the transmission loss is reduced to reduce the reception gain. Can be improved.

Further, it also has an advantage that it also serves as a colored opaque layer as an insulating layer.

[Brief description of drawings]

FIG. 1 is a front view showing Example 1 and Example 2 in which the glass antenna of the present invention is provided on a rear window glass for an automobile.

FIG. 2 is a front view showing a third embodiment in which the glass antenna of the present invention is provided on a rear window glass for an automobile.

FIG. 3 is a front view showing Example 4 and Example 5 in which the glass antenna of the present invention is provided on a rear window glass for an automobile.

[Explanation of symbols]

1 plate glass 2 anti-fogging heating wire 3 _{1 to} 3 ₅ first antenna 4 ₁ to 4 ₅ first feeding point 5 colored opaque layer 6 _{1 to} 6 ₅ second antenna 7 _{1 to} 7 ₅ second feeding point

Claims (6)

[Claims] 1. A first antenna having at least a horizontal filament, a vertical filament or a horizontal filament and a vertical filament is provided within the lower layer of a colored opaque band formed on the peripheral portion of a window glass for an automobile, and the coloring is performed. A second antenna, which is capacitively coupled to at least a part of the first antenna, is provided on an upper layer of the opaque band, and an inner conductor of a coaxial cable is provided in the second antenna.
A glass antenna for an automobile, characterized in that an outer conductor of a coaxial cable is connected to the first antenna. 2. A first antenna having at least a horizontal filament, a vertical filament or a horizontal filament and a vertical filament is provided within the lower layer of the colored opaque band formed on the peripheral portion of the window glass for automobiles, and the coloring is provided. A second antenna that capacitively couples with at least a part of the first antenna is provided on the upper layer of the opaque band, and the inner conductor of the coaxial cable is provided with the first antenna.
A glass antenna for an automobile, characterized in that an outer conductor of a coaxial cable is connected to the second antenna. 3. The glass antenna for an automobile according to claim 1 or 2, wherein all of the first antenna is provided in a lower layer of the colored opaque band. 4. The glass antenna for an automobile according to claim 1, wherein a part of the first antenna is provided so as to protrude from the colored opaque band. 5. A glass antenna for an automobile, wherein at least one antenna different from the antennas according to any one of claims 1 to 4 is adapted to receive diversity. 6. A plurality of antennas according to any one of claims 1 to 4 are provided, and a plurality of antennas are provided, or another antenna is added to the plurality of antennas for diversity reception. Glass antenna for automobiles.